GoldenCheeetah locked in Full Screen mode and menus don't work - GoldenCheetah/GoldenCheetah GitHub Wiki

There are some reports of this issue, mainly in Windows and after an upgrade, and it could not be solved by reinstalling and/or restoring the user data from backup.

The initial main window state is recorded in GoldenCheetah.ini settings file, removing that file when GoldenCheetah is closed and restarting, typically solves the issue.

See the FAQs on Data for the specific location of GoldenCheetah.ini file, since it is Operating System dependent.