RealVNC Viewer Parameter Reference

You can configure VNC Viewer by changing parameters either in the Preferences > Expert dialog box, at the command line, or using policy.

Note that:

• VNC Viewer parameters may be overridden by VNC Server parameters; where so is clearly stated.
• Changes made to parameters in the Preferences > Expert dialog box take effect when the OK button is clicked, unless otherwise stated.
• Changes made in the Preferences > Expert dialog box for VNC Viewer as a whole can be overridden for connections to a particular computer in its Properties > Expert dialog box.
• If a parameter has a Since version, the number is that of the VNC Server version that enables this functionality.

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AcceptBell

Platform	Default value
Linux	TRUE

Specify FALSE to suppress system beeps produced by the VNC Server computer.

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AllowCloudRelay

Platform	Default value	Since
All	TRUE	6.4.0

Specify FALSE to prevent cloud connections from the VNC Viewer computer if they would be relayed via RealVNC’s cloud service.

All cloud connections are brokered by RealVNC’s cloud service. Where possible, the cloud service then negotiates peer-to-peer sessions between endpoints, so session data is transmitted directly between them; this is likely to be more performant. However, intermediate network hardware may mean this is not possible, so the cloud service automatically falls back to relaying session data; this ensures cloud connections succeed. Note that session data relayed via our cloud service is encrypted end-to-end, so cannot be deciphered by RealVNC, nor anyone else.

Setting this parameter to FALSE will cause an unquantifiable percentage of cloud connections to fail. However, it may be useful in the context of some regulatory compliance regimes, to guarantee that session data will never be transmitted via third party servers.

An equivalent VNC Server AllowCloudRelay parameter is available to prevent cloud connections to particular computers.

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AllowDragBetweenWindows

Platform	Default value	Since
All	TRUE	7.12.0

Specify FALSE to disallow windows on the VNC Server computer’s desktop to be dragged between VNC Viewer monitor windows.

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AllowMainClose

Platform	Default value	Since
All	FALSE	6.0.0

Specify TRUE to keep active session windows open if the main VNC Viewer app window is closed.

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AllowSignIn

Platform	Default value	Since
All	TRUE	6.0.0

Specify FALSE to prevent users signing in to VNC Viewer using their RealVNC account credentials. This means they can only establish direct connections, not cloud connections to team computers, nor sync their address book with other VNC Viewer devices.

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AudioVolume

Platform	Default value	Since
All	100	6.19.923

Sets the audio volume level (0-100). To mute audio, set to 0.

By setting this parameter (e.g. via Group Policy), it will disable "New: Hear audio from your remote computer!" prompt that appears for the first audio-enabled VNC session. 

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AuthCertificate

Platform	Default value	Since
All	<auto>	6.1.0

Specify a hash of the public key certificate to send to a VNC Server computer set up to use smartcard/certificate store authentication. By default, <auto> queries for a public key to use.

Specify an empty value (AuthCertificate=) to disable key-based authentication. 

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AutoReconnect

Platform	Default value
All	TRUE

Specify FALSE to prevent VNC Viewer automatically reconnecting to VNC Server in certain circumstances, for example if the current user account is logged or switched out.

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BumpScrollSpeed

Platform	Default value	Since
All	10	6.0.0

Specify a number between 1 and 9 to slow bump scrolling down when in full screen mode, or between 11 and 100 to speed it up.

See also: FullScreen

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ChangeServerDefaultPrinter

Platform	Default value
All	TRUE

Specify FALSE to not change the default printer of the VNC Server computer. A connected VNC Viewer user must explicitly select a VNC printer at print-time.

By default, the VNC Server computer’s default printer is changed to that of the first VNC Viewer computer that connects.

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ClientCutText

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected VNC Viewer user pasting text to the VNC Server computer.

See also: ServerCutText

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ClipboardKeystrokesEnable

Platform	Default value	Since
All	2	7.12.0

Enable sending clipboard contents as keystrokes. Specify one of the following:

• 0 to disable
• 1 to enable
• 2 to enable when showing the logon desktop on the VNC Server computer.

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ColorLevel

Platform	Default value
All	pal8

Specify one of the following values to determine the picture quality of the VNC Server computer desktop:

• rgb111 to use 8 colors
• rgb222 to use 64 colors
• pal8 to use 256 colors
• full to use full color

Using more colors gives a better user experience, at a potential cost in performance.

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ColorSpaceRGB

Platform	Default value	Since
Mac	sRGB	7.9.0

Render a VNC Server computer's desktop using a standard color space sRGB (sRGB), a device-independent (Generic), or a device-dependent (Device), RGB color space.

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DotWhenNoCursor

Platform	Default value
All	TRUE

Specify FALSE to not show a local cursor if an application running on the VNC Viewer computer is set to show an invisible cursor.

By default, VNC Viewer displays a dot cursor in this circumstance.

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DynamicResolution

Platform	Default value	Since
All	FALSE	7.6.0

Change VNC Server desktop's resolution to the size of the VNC Viewer application window.

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Emulate2

Platform	Default value
Mac	FALSE

Specify TRUE if the VNC Viewer computer’s mouse has one button but the mouse attached to the VNC Server computer has two.

A connected VNC Viewer user can emulate the missing button by holding down the Ctrl key while clicking.

See also: Emulate3

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Emulate3

Platform	Default value
All	FALSE

Specify TRUE if the VNC Viewer computer’s mouse has two buttons but the mouse attached to the VNC Server computer has three.

A connected VNC Viewer user can emulate the missing middle button by clicking the left and right buttons simultaneously.

See also: Emulate2

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EnableAnalytics

Platform	Default value	Since
All	FALSE	6.0.0

Specify TRUE to allow RealVNC to collect anonymous usage data to help improve our products.

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EnableChat

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected VNC Viewer user participating in a chat session.

The user can still view chat messages exchanged by other users connected at the same time.

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EnableRemotePrinting

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected VNC Viewer user printing a VNC Server computer file to a local printer.

See also: ChangeServerDefaultPrinter

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EnableToolbar

Platform	Default value
All	TRUE

Specify FALSE to disable the toolbar, preventing a connected VNC Viewer user performing key operations.

See also: MenuKey, ToolbarIconSize

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EnableUdpRfb

Platform	Default value	Since
All	TRUE	6.4.0

For direct connections to VNC Server with an Enterprise subscription, specify:

• FALSE if you only want to establish TCP connections, and not try UDP first.
• FORCE if only want to establish UDP connections, and not fall back to TCP.

By default, VNC Viewer trys to establish a UDP connection first, which is likely to make the remote access session more responsive, before falling back to TCP if (for example) UDP is not enabled in your network environment.

See also the VNC Server IpListenProtocols parameter.

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Encryption

Platform	Default value
All	Server

Determine, in conjunction with VNC Server, whether:

• Remote control sessions are encrypted end-to-end.
• The exchange of authentication credentials is encrypted, but subsequent sessions are not. This means session data may be susceptible to interception by third parties.

• Server to let VNC Server choose. By default, direct connections will be encrypted end-to-end unless the VNC Server Encryption parameter is set to PreferOff or AlwaysOff.
• AlwaysMaximum to request that direct connections be encrypted end-to-end using 256-bit AES. This request is granted unless the VNC Server Encryption parameter is set to Alwaysoff.
• AlwaysOn to request that direct connections be encrypted end-to-end using at least 128-bit AES. This request is granted unless the VNC Server Encryption parameter is set to Alwaysoff.
• PreferOn to prefer that direct connections be encrypted end-to-end using at least 128-bit AES. This request is granted unless the VNC Server Encryption parameter is set to Alwaysoff.
• PreferOff to prefer that the exchange of authentication credentials be encrypted using at least 128-bit AES, but that sessions themselves need not be encrypted. This may improve performance. This request is granted unless you are making a cloud connection or the VNC Server Encryption parameter is set to AlwaysMaximum or AlwaysOn

See also: SecurityNotificationTimeout, WarnUnencrypted, RsaPrivateKeyFile

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FetchDir

Platform	Default value
All	<platform-specific>

Specify a full path to a directory to which files transfered from the VNC Server computer are downloaded, for example C:\Users\johndoe\MyDocuments.

By default, files are downloaded:

• Under Windows and Linux, to the VNC Viewer users’s Desktop directory.
• Under Mac, to the user’s Downloads directory.

See also: ShareFiles

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FullScreen

Platform	Default value
All	FALSE

Specify TRUE to display an active VNC Viewer session window in full screen. Note under Mac, the behavior is determined by UseLegacyFullScreenMode.

See also: FullScreenChangeResolution, UseAllMonitors

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FullScreenChangeResolution

Platform	Default value
Windows	FALSE

Specify TRUE to change the VNC Viewer computer’s screen resolution to that of the VNC Server computer if FullScreen is TRUE.

See also: UseAllMonitors

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FullscreenMonitors

Platform	Default value	Since
All		7.10.0

In multi-window mode, show these monitors from the VNC Server computer in full screen mode. Use the toolbar or F8 menu on each return to windowed mode.

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GrabKeyboard

Platform	Default value
Linux	1

Specify one of the following values to determine whether VNC Viewer monopolizes its computer keyboard, preventing other applications receiving keyboard input.

• 0 to never grab the keyboard.
• 1 to grab the keyboard if FullScreen is TRUE.
• 2 to always grab the keyboard.

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HideCloseAlert

Platform	Default value
All	FALSE

Specify TRUE to close VNC Viewer silently if a user is disconnected unexpectedly, perhaps because VNC Server has stopped. Use in conjunction with AutoReconnect set to FALSE in order to exit VNC Viewer cleanly if run from a script.

By default, a newly-disconnected user is informed of the reason in a message box that must be acknowledged before VNC Viewer can close.

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HideScreenshots

Platform	Default value	Since
All	FALSE	6.0.0

Specify TRUE to replace all desktop preview screenshots with a placeholder image.

Note this does not remove desktop previews, just hides them. To remove desktop previews entirely, navigate to File > Preferences > Privacy > Forget all sensitive data.

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Identities

Platform	Default value
Mac, Linux	$HOME/.vnc/identities

Specify a path to a file storing signatures uniquely identifying instances of VNC Server already connected to.

Depending on the value of VerifyID, a connecting user is warned if a VNC Server signature is new or has changed, which might help prevent connections to unintended or illegitimate destinations.

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InterpretDeadKeys

Platform	Default value
Linux	FALSE

Specify TRUE to compose a character from a dead key and the key-to-be-modified before sending the combination to VNC Server. This may be useful for connections to VNC Server computers that cannot natively compose particular symbols.

By default, the dead key and the key-to-be-modified are sent as separate key presses.

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KeepAliveInterval

Platform	Default value
All	60

Specify a number of seconds for VNC Viewer to wait between sending keep alive messages to VNC Server, to maintain connections that might otherwise be considered idle by routers or gateways (perhaps because the VNC Viewer session window is minimized), and unexpectedly terminated.

Specify 0 to not send keep alive messages. Connections may be terminated unexpectedly.

See also: KeepAliveResponseTimeout

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KeepAliveResponseTimeout

Platform	Default value
All	30

Specify a number of seconds for VNC Viewer to wait for a response to a keep alive message from VNC Server.

It might be useful to set this to a value lower than the standard TCP timeout if connections are likely to be subject to network errors. By default, VNC Viewer waits for the standard TCP timeout before closing the VNC Viewer session window.

See also: KeepAliveInterval

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LeftCmdKey

Platform	Default value
Mac	Alt_L

Specify one of the following values to send a particular keysym to the VNC Server computer when the left Command key is pressed:

• Alt_L
• Alt_RLeftOptKey
• Super_L
• Super_R
• ExtendedChars

By default, for a connection to a:

• Windows or Linux computer with a PC keyboard, the left Alt key is simulated, which means that pressing left Command+F has the effect of opening the File menu on most Windows applications.
• Mac computer, it is recommended you do not change this parameter unless you are also able to make the same change to the VNC Server LeftCmdKey parameter, which by default maps the Alt_L keysym back to the left Command key.

Note that ExtendedChars refers to the key typically used to create extended characters, for example AltGr on non-US PC keyboards.

See also: LeftOptKey, RightCmdKey, RightOptKey

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LeftOptKey

Platform	Default value
Mac	ExtendedChars

See LeftCmdKey, but for the left Option key.

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Locale

Platform	Default value
All

Specify one of the following values to choose a display language:

• en_US for English
• fr_FR for French
• de_DE for German
• es_ES for Spanish

By default, this parameter is empty, and the VNC Viewer user interface inherits the desktop language of the currently logged-on computer user, or falls back to English if this language has not yet been translated. Note VNC Viewer must be restarted for a change to this parameter to take effect.

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Log

Platform	Default value
All	*:stderr:0

Specify an ordered, comma-separated list of activities to record, each of the form:

<log>:<target>:<level>

where:

• <log> determines the type of activity to record, for example connection, printing or file transfer activity, or * to record all. To see a list of available activities, examine the Log names section in the advanced help output (run the command vncviewer -help all).

• <target> determines the output destination:

  • Under Windows, either stderr, file (configured using LogDir and LogFile), or EventLog (to write to the Windows Event Log service).
  • Under Mac and Linux, either syslog (configured using SyslogFacility under Linux), stderr or file.

• <level> determines severity: 0 includes only serious errors, 10 includes basic audit information, 30 includes general information, and 100 includes all possible information, potentially including keystrokes.

  If you use SysLog, <level> translates as follows: 0 is Syslog 3 (Error), 1 to 5 is 4 (Warning), 6 to 10 is 5 (Notice), 11 to 30 is 6 (Informational), and more than 30 is 7 (Debug).

Consider the following example:

*:file:10,CConnection:file:100

• The first entry (*:file:10) specifies that all activity is recorded to file at level 10.
• The second entry (CConnection:file:100) overrides this for connection activity, recording it (to the same file) at level 100.

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LogDir

Platform	Default value
All	<platform-specific>

Specify a directory in which VNC Viewer should create a LogFile, for example C:/Data/RealVNCLogs. This location must be writable.

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LogFile

Platform	Default value
All	vncviewer.log

Specify a name for the file VNC Viewer should create in LogDir, for example realvnc debug.log.

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MaxServersToList

Platform	Default value
All	0

Maximum number of Servers to list in a team, or 0 to use the default value set by RealVNC services (1,000).

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MenuKey

Platform	Default value
All	F8

Specify a function key in the range F1 to F12 to raise the shortcut menu when the active VNC Viewer session window has focus.

Specify an empty value (menukey=) to disable the shortcut menu, preventing a connected VNC Viewer user performing particular operations.

See also: EnableToolbar

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Monitor

Platform	Default value
Windows

Specify a monitor attached to the VNC Viewer computer to display the VNC Viewer app window on, for example \\.\DISPLAY2.

By default, or if the specified value is not recognized, VNC Viewer is displayed on the primary monitor (equivalent to \\.\DISPLAY1).

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PasswordKeychain

Platform	Default value	Since
Mac		6.0.0

Specify the name of, or path to, a keychain in which to store VNC Server passwords that VNC Viewer has been asked to remember.

Specify an empty value (PasswordKeychain=) to use the default system keychain.

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PasswordMasterTimeout

Platform	Default value	Since
All	900	6.0.0

The amount of time, in seconds, that VNC Viewer remembers its master password for when a VNC Viewer user attempts to connect.

Subsequently, the user must enter the master password in order to connect to any computer.

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PasswordStoreOffer

Platform	Default value	Since
All	TRUE	6.0.0

Specify FALSE to not give users the opportunity for VNC Viewer to remember VNC Server passwords.

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PointerCornerSnapThreshold

Platform	Default value
All	30

Specify a number of pixels from each corner of the active VNC Viewer session window, on each axis.

If a connected user moves the VNC Viewer computer’s mouse cursor out of the window within this area, the VNC Server computer’s mouse cursor is snapped to the corner. This may be useful for connections to computers that trigger special effects in the corners, for example Windows 8 and Mac OS X 10.8 (Mountain Lion).

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PointerEventInterval

Platform	Default value
All	0

Specify a number of milliseconds to wait before sending mouse events such as cursor movements, clicks, and scrolls to the VNC Server computer.

Increasing this value may make connections over a low-bandwidth network more responsive.

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PreferredEncoding

Platform	Default value
All	ZRLE

Specify one of the following values to request that VNC Server send screen updates in a particular encoding:

• JPEG
• Zlib
• ZRLE
• ZRLE2
• TRLE
• Hextile
• Raw
• JRLE

For more information on encodings, consult RFC 6143.

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ProtocolVersion

Platform	Default value
All

For direct connections to VNC Server with an Enterprise subscription, specify a particular value to request that VNC Server use only that version or lower of the underlying RFB protocol.

• 3.3
• 3.8
• 4.0
• 4.1
• 5.0
• 6.0

A lower version might be useful for connections to legacy third party VNC-compatible Server apps that do not offer support for subsequent versions of the RFB protocol.

By default, the latest version of the RFB protocol is requested.

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ProxyAutoConfig

Platform	Default value
Windows

URL of proxy auto-config (PAC) script.

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ProxyServer

Platform	Default value
All	<system>

Specify the proxy type, network address and port number of a proxy server if the VNC Viewer computer is protected by one, for example http://myhttpproxyserver.com:8080 or socks://mysocksproxyserver.com:8080.

The default value of <system>:

• Under Windows, uses the proxy server settings of Microsoft Internet Explorer.
• Under Linux, uses standard proxy server environment variables or libproxy.
• Under Mac, uses the proxy server settings of the Network system preference.

For VNC Viewer 6 or later, if the proxy server requires a password, first run vncpasswd to base64-encode that password as follows:

vncpasswd -print

Then, store the output as ProxyPassword=<base64-encoded-password>:

• Under Windows, in the HKCU\Software\RealVNC\vncviewer Registry key.
• Under Linux or Mac, in the ~/.vnc/config.d/vncviewer configuration file.

The vncpasswd utility is available in the same directory as VNC Server (download VNC Connect if you don’t have VNC Server). Please note that the ProxyPassword parameter does not appear in the Preferences > Expert dialog box.

See also: ProxyUserName, ProxyPassword

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ProxyTcpRfb

Platform	Default Value	Since
All	TRUE	6.0.0

Specify FALSE to bypass a proxy server identified by ProxyServer in the following circumstances:

• For a cloud connection, after the initial connection negotiation phase. This means that communication between the VNC Viewer computer and the RealVNC cloud service is proxied until the VNC Viewer user successfully authenticates, but then the remainder of the session is conducted peer-to-peer.
• For a direct connection. Note the remote computer must have an Enterprise subscription applied.

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ProxyUserName

Platform	Default value
All

Specify a user name if ProxyServer requires authentication.

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Quality

Platform	Default value	Since
All	AUTO	6.0.0

Specify HIGH or LOW to determine picture quality, irrespective of network speed. This may affect performance.

Specify CUSTOM to control the picture quality using the PreferredEncoding and ColorLevel parameters.

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RelativePtr

Platform	Default value
All	FALSE

Specify TRUE to send relative changes in mouse cursor position to the VNC Server computer, rather than absolute co-ordinates.

This may be useful to synchronize the mouse cursors of the VNC Viewer and VNC Server computers, if one is diverging from the other, which can happen if an application running on the VNC Server computer does not support absolute mouse events, or for connections to KVM-over-IP switches. Note that a connected VNC Viewer user will not be able to move the mouse cursor outside the VNC Viewer app window.

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RightCmdKey

Platform	Default value
Mac	Super_L

See LeftCmdKey, but for the right Command key.

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RightOptKey

Platform	Default value
Mac	ExtendedChars

See LeftCmdKey, but for the right Option key.

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RsaPrivateKeyFile

Platform	Default value
Mac, Linux	<platform-specific

Specify the full path to a file storing a private key for VNC Viewer.

If the private key is missing or corrupt, connections cannot be established. To generate a new private key, restart VNC Viewer.

See also: Encryption

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ScalePrintOutput

Platform	Default value
All	True

Specify FALSE to print VNC Server computer files at their actual size.

By default, pages are scaled to fit the boundaries of the local printer’s paper.

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Scaling

Platform	Default value
All	FitAutoAspect

Specify one of the following values to determine whether the VNC Server computer’s desktop is scaled relative to the size of the active VNC Viewer session window:

• None to not scale the VNC Server computer’s desktop. If it is bigger than the session window, scroll bars appear. The window cannot be resized larger than the desktop.
• FitAutoAspect to automatically choose between AspectFit, FitWidth or FitHeight. Available from version 6.1.0.
• FitAuto to automatically choose between FitAuto, Fit, FitWidth or FitHeight. Available from version 6.1.0.
• Fit to scale the desktop to the size of the session window.
• AspectFit to scale the desktop to the size of the session window, but retain the aspect ratio.
• FitWidth to scale the desktop to the width of the session window. Available from version 6.1.0.
• FitHeight to scale the desktop to the height of the session window. Available from version 6.1.0.
• <pixel-width>x<pixel-height> to scale the desktop to the specified session window size. The window cannot be resized larger.
• <pixel-width>x to scale the desktop to the specified session window width; the height is determined by the aspect ratio. The window cannot be resized larger.
• x<pixel-height> to scale the desktop to the specified session window height; the width is determined by the aspect ratio. The window cannot be resized larger.
• <percentage-size>% to scale the desktop to a percentage of the size the session window would be were this parameter set to None. The window cannot be resized larger.
• <percentage-width>%x<percentage-height>% to scale each axis of the desktop to a percentage of the size the session window would be were this parameter set to None. The window cannot be resized larger.

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ScalingMonitors

Platform	Default value	Since
All	FALSE	7.10.0

In multi-window mode, apply the defined Scaling to each of the listed of monitors.

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ScalingQuality

Platform	Default value
Mac	2

Specify one of the following values to determine the rendering quality when the VNC Server computer’s desktop is scaled:

• 0 to use standard quality.
• 1 to use low quality (the desktop is rendered quicker).
• 2 to use medium quality.
• 3 to use high quality (note this might be CPU-intensive).

See also: Scaling

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ScrollWheelAccel

Platform	Default value
Mac	TRUE

Specify FALSE to ignore the speed at which the mouse is set to scroll in System Preferences, causing turns of the mouse wheel to scroll pages at a regimented speed.

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ScrollWheelThreshold

Platform	Default value
Windows	120

Level at which cumulative mouse wheel messages generate a scroll event, with 0 meaning generate an event for every message.

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SecurityNotificationTimeout

Platform	Default value
All	2500

Specify the number of milliseconds to display encryption status to a newly-connected user for.

The status is displayed at the bottom of the active VNC Viewer session window, in a green bar if the connection is encrypted and in a red bar if it is unencrypted. The connected VNC Viewer user can dismiss the status bar at any time.

Specify 0 to suppress the display of the encryption status.

See also: Encryption

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SelectDesktop

Platform	Default Value
All

Specify the name of a computer to connect to automatically when a connection is established to a suitably-enabled ADDERLink KVM-over-IP switch.

See also: RelativePtr

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SendInitialClipboard

Platform	Default value	Since
All	FALSE	6.19.107

Specify TRUE to share the current clipboard contents with the VNC Server computer as soon as the session starts.

See also: ClientCutText

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SendKeyEvents

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected user controlling the VNC Server computer using the VNC Viewer computer’s keyboard.

See also: SendPointerEvents

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SendMediaKeys

Platform	Default Value
Windows, Mac	TRUE

Specify FALSE to cause media keys such as Play and Volume Up to be interpreted by the VNC Viewer computer. By default, these keys are sent to, and interpreted by, the VNC Server computer.

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SendPointerEvents

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected user controlling the VNC Server computer using the VNC Viewer computer’s mouse.

See also: SendKeyEvents

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SendPrimary

Platform	Default value
Linux	TRUE

Specify FALSE to send the CLIPBOARD selection to VNC Server in preference to the PRIMARY selection (that is, the currently highlighted content).

See also: ClientCutText

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SendSpecialKeys

Platform	Default Value
Windows, Mac	TRUE

Specify FALSE to cause the following keys and key combinations to be interpreted by the VNC Viewer computer:

• Windows: The Windows key (also known as Start or Super), PrtScn (Print Screen), Alt+Tab, Alt+Esc, Ctrl+Esc
• Mac: System shortcuts such as Cmd+Tab and the Spotlight shortcut

By default, these keys and key combinations are sent to, and interpreted by, the VNC Server computer.

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SendVolumeKeys

Platform	Default value
Windows, Mac	FALSE

Send volume up/down/mute keys to the VNC Server computer.

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ServerClipboardGraceTime

Platform	Default Value
All	1000

Specify a number of milliseconds to wait before discarding text copied from the VNC Server computer if VNC Viewer no longer has focus.

See also: ServerCutText

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ServerCutText

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected user copying text on the VNC Server computer and pasting it to the VNC Viewer computer.

See also: ClientCutText

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SessionRecordAllowDirOverride

Platform	Subscription	Default value	Since
All	Enterprise, Professional	TRUE	6.21.920

The user can override the default storage directory.

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SessionRecordAllowUserControl

Platform	Subscription	Default value	Since
All	Enterprise, Professional	TRUE	6.21.920

The user can start and stop session recording as required.

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SessionRecordAllSessions

Platform	Subscription	Default value	Since
All	Enterprise, Professional	FALSE	6.21.920

Upon connection, all sessions will be recorded to a webm format video file, if the VNC Server supports recording.

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SessionRecordEncodeSpeed

Platform	Subscription	Default value	Since
All	Enterprise, Professional	5	6.21.920

Session recorder encoder's coding speed (0-9). A higher speed yields faster coding at the cost of lower compression efficiency.

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SessionRecordEncodingFrameRate

Platform	Subscription	Default value	Since
All	Enterprise, Professional	20	6.21.920

If non-zero then this is the number of frames per second that are encoded. Otherwise all frames are encoded.

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SessionRecordNewFileOnIncrease

Platform	Subscription	Default value	Since
All	Enterprise, Professional	FALSE	6.22.207

If  TRUE  then start recording to a new file whenever the desktop resolution increases, otherwise scale frames to the size of the first recorded frame.

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SessionRecordStorageFolder

Platform	Subscription	Default value	Since
All	Enterprise, Professional	<platform-specific>	6.21.920

The default storage folder for session recording files.

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Shared

Platform	Default value
All	TRUE

Specify FALSE to request that other VNC Viewer users be disconnected when a connection is established.

VNC Server complies with this request providing the VNC Server DisconnectClients parameter is TRUE.

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ShareFiles

Platform	Default value
All	TRUE

Specify FALSE to prevent a connected VNC Viewer user transferring files to and from the VNC Server computer.

See also: FetchDir

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ShowSplash

Platform	Default value	Since
All	TRUE	7.13.0

Show a splash dialog when first run.

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ShowTeamGroups

Platform	Default value	Since
All	TRUE	7.6.0

Show the online team groups.

This parameter controls whether RealVNC Viewer displays cloud-connected computers within the groups as defined in the RealVNC Connect Portal.

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SingleSignOn

Platform	Default value
All	TRUE

Specify FALSE to prevent a user authenticating automatically to VNC Server using credentials already supplied to log on to the VNC Viewer computer (even if VNC Server is set to use the single sign-on authentication scheme, and all the necessary network infrastructure is in place). See Setting up Single Sign-on Authentication (SSO)

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SyslogFacility

Platform	Default value
Linux	user

Specify one of the following facilities for syslog to use, if available on the system:

• daemon
• auth
• authpriv
• security
• local0..local7

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TlsProfile

Platform	Default value
All	Normal

The security strength to enforce when making TLS connections. For 'Normal', TLS 1.2 is mandated, no broken fallback ciphers are allowed, and key strength is checked for security (no SHA-1 or small keys). Selecting 'High' limits cipher choices to AES-256 with no legacy ciphers.

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ToolbarPin

Platform	Default value	Since
All	FALSE	7.12.0

Pin the toolbar so that it is always shown (if EnableToolbar is TRUE)

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ToolbarIconSize

Platform	Default value
All	24

Specify one of:

• 16
• 24
• 32

to determine the size in pixels of the icons on the VNC Viewer toolbar.

See also: EnableToolbar

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UriSuppressConnectionPrompt

Platform	Default value	Since
All	FALSE	6.22.826

Specify TRUE to suppress the confirmation required when launching VNC Viewer using a URI, such as from the VNC Connect Portal.

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UpdateScreenshot

Platform	Default value	Since
All	TRUE	6.0.0

Specify FALSE to prevent VNC Viewer updating desktop preview screenshots.

See also: HideScreenshots

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UseAllMonitors

Platform	Default value
Windows, Mac	FALSE

Specify TRUE to display the VNC Server computer’s desktop across all available monitors if FullScreen is TRUE.

---

UseDisplayCapture

Platform	Default value
Mac	TRUE

Specify FALSE to cause key combinations such as Cmd+Tab to be interpreted by the VNC Viewer computer if FullScreen is TRUE. By default, key combinations are sent to the VNC Server computer.

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UseLegacyFileTransfer

Platform	Default value	Since
All	FALSE	7.9.0

Specify TRUE to use the legacy version of File Transfer instead of File Manager.

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UseLegacyFullScreenMode

Platform	Default value
Mac	FALSE

Specify TRUE on Mac OS X 10.7+ computers to use legacy VNC rather than platform-native full screen mode if FullScreen is TRUE. Note VNC Viewer must be restarted in order for a change to this parameter to take effect.

This might be useful if UseAllMonitors is TRUE to display the active VNC Viewer session window across multiple monitors.

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UseLocalCursor

Platform	Default value
All	TRUE

Specify FALSE to display the cursors of both the VNC Viewer and VNC Server computer (the former is represented by a dot). This may be useful if the connection suffers from high latency, though note VNC Server may be required to send more screen updates.

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UserName

Platform	Default value	Not in
All	<user-account-name>	6.0.0

Specify the user name to use to authenticate to VNC Server, or $USER to expand the current system user name.

If your user name includes a $ character, escape it with another, for example $$au$$age$$.

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VerifyID

Platform	Default value
All	2

Specify one of the following values to determine whether or not to warn a connecting user that VNC Server’s signature status has changed (note that in particular, a different signature may indicate a man-in-the-middle attack):

• 0 to suppress signature warnings.
• 1 to ensure warnings appear for different signatures, and for computers that no longer have a signature.

By default, warnings appear for new and for different signatures, and for computers that no longer have a signature.

See also: Identities

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WarnUnencrypted

Platform	Default value
All	TRUE

Specify FALSE to prevent a connecting VNC Viewer user being warned that the connection will be unencrypted before it is established.