CloudCompare forum

When I was using CC, I clicked on the fullscreen display and then it got stuck with a bug. When I closed and reopened the software, it was always in fullscreen mode, and the menu buttons in the navigation bar couldn't be used, nor could I exit fullscreen, so I couldn't close the software normally. When I uninstalled and reinstalled the software, it opened in fullscreen mode right away. Restarting my computer didn't help.

So, if the F9 or F11 shortcuts don't help, you can use 'regedit' - I assume you are on Windows? - to remove all the keys of CloudCompare (under 'Computer\HKEY_CURRENT_USER\Software\CCCorp\CloudCompare')