Overview

You may be unable to launch LanGuard. When launching, you are getting the error "An instance of GFI LanGuard is already running in another logon session!".

Solution

It is possible that an anti-virus software (such as TrendMicro) is preventing LanGuard from updating an environment variable to signify that it has stopped running. To resolve this issue, follow the steps below:

1. Disable the antivirus software or any other real-time protection that you may have running, reboot the server, and try launching LanGuard again to confirm the issue.
2. Make sure that your antivirus and other real-time protection software are correctly configured to work with LanGuard. Refer to this article for more details.