RealVNC Connect

By default, RealVNC Viewer and RealVNC Server record basic information about connection activity in the system's own logging facility, as well logging application activity to a file.

Default log destinations

The following table lists the default destinations for log output from RealVNC Server and RealVNC Viewer:

RealVNC Server

RealVNC Viewer

The following notes apply to the tables above:

1. RealVNC Server and RealVNC Viewer require Windows Event Log Service to be running, and that Event Viewer > Windows Logs > Application > Properties is set to overwrite as needed.
   If the service is not running or the event log is full, connections cannot be established.
2. Using Linux, RealVNC Server running in Service mode. can be configured to log to different facilities using the SyslogFacility parameter.

3. Using Linux, the default destination for RealVNC Server in Virtual Mode is Standard Error (stderr). However, vncserver-virtual automatically redirects this to file at:

   ~/.vnc/<computer>:<display-number>.log

   Please note that the output of the X Server session is also included.

Under Linux and macOS, RealVNC Server also automatically logs connections authenticated using system authentication or single sign-on schemes to the syslog AUTHPRIV facility. This is typically located at /var/log/auth.log and /var/log/secure/log respectively.

Customising logfile name and location

Logging to file is determined by the LogDir and LogFile parameters. For the default filename and directory, please refer to the Default log destinations section above.

For RealVNC Viewer, please note that the destination file and directory must have writable permissions for a standard user account and must not require administrative privileges to view / write to.

Log file rotation

v7.14.0 and later

From RealVNC Viewer/Server 7.14.0 and RealVNC Connect 8.0.0 and later, RealVNC Connect will rotate the log file to a timestamped .log file each time the program is restarted:

*Note: v7.14.0 will save them as vncviewer.log.<timestamp> and vncserver.log.<timestamp>.

How long the logs are stored is dependent on the LogKeepDays parameter in RealVNC Viewer and RealVNC Server respectively; the default is 30 (days).

v7.13.1 and earlier

The destination files contents are overwritten each time the program is restarted, retaining the current instance's logs and 1 previous instance in a .log.bak file.

Generating debug logs

When contacting RealVNC Support, the support team rely on comprehensive debug log files to troubleshoot problems. For more information about how to generate debug logs please see our dedicated article here: How do I generate debug logs in RealVNC Connect?

Recording information about other programs and sub-processes

The Log, LogFile and LogDir parameters can be used to record information about RealVNC Connect programs – excluding RealVNC Viewer and RealVNC Server – along with its sub-processes. This may be useful if RealVNC's Support team requests that you dig deeper into any problems you may encounter.

Windows

You can apply the above parameters to the following programs and sub-processes by creating keys in the Windows Registry or for other programs via the command line.

For example, to create a log file for the RealVNC Server in Service Mode user interface:

1. Using Registry Editor, navigate to HKEY_CURRENT_USER\Software\RealVNC.
2. Select New > Key from the shortcut menu, and create vncserverui-service.
3. Select New > String Value from the shortcut menu, and create Log.
4. Select Modify from the shortcut menu, and specify appropriate Value data, for example *:file:100.

Repeat steps 3 and 4 for the LogFile and LogDir parameters, if necessary. Restart the program to create the new log file.

To create a log file for a program at the command line, apply parameters before any command, for example:

vnclicense.exe -Log=*:file:100 -LogFile=license.log -add <offline license>

macOS

You can apply the logging parameters to the following programs when run from the command line:

• vnclicense
• vnclicensewiz

Do so before any command, for example:

/Library/vnc/VNC\ Server\ Licensing.app/Contents/MacOS/vnclicensewiz -Log=*:file:100

*Two files are created for the RealVNC Server Licensing Wizard:

• ~/Library/Logs/vnc/vnclicensewiz.log
• /Library/Logs/vnclicensewiz_helper.log

macOS Catalina (and later) requires you change the shell to bash before running this command. 

Linux

You can apply parameters to the following programs when run from the command line:

• vnclicense
• vnclicensewiz

Do so before any command, for example:

sudo vnclicense -Log=*:file:100 -LogDir=/home/dev/logs -add <offline license>

On-Demand Assist

By default, On-Demand Assist logs application activity to a file.

Default log destinations

Please note, if you have applied custom branding to your On-Demand Assist app the folder and file name will be OnDemandAssistByYourCompanyName instead.

Windows

%localappdata%\OnDemandAssistByRealVNC\OnDemandAssistByRealVNC.log

macOS

~/Library/Logs/OnDemandAssistByRealVNC/OnDemandAssistByRealVNC.log

Linux

~/.OnDemandAssistByRealVNC/OnDemandAssistByRealVNC*.log

Log file rotation

On-Demand Assist rotates the log file to a timestamped .log file each time the program is restarted. Log files will be kept for 30 days.

Generating debug logs

When contacting RealVNC Support, the support team rely on comprehensive debug log files to troubleshoot problems. For more information about how to generate debug logs please see our dedicated article here: How do I generate debug logs in RealVNC Connect?