I hate it when stuff works and then it doesn't! I just want stuff to keep working the way I had it!
That's why I have VirtualBox installed and on it a working version of Windows 11 (without activation, no need for that).
When I test any program, whatever it is, I do that in VirtualBox Windows. Can make snapshots of the situation I am in and if there's any problem go back to the former snapshot.
If a program causes whatever troubles, I just close the VirtualBox window, telling the program to go back to the last saved snapshot.
Never have any problems with tested software that spoils my real system!
The only updates I do on the real system are the official updates (no Beta versions) of programs I already have in use.
So my test with the eM-Client 11 Beta I did on this testsystem. After concluding it was not the thing I liked I erased the last situation.
I later on tried to imitate the problem you described in #294 with the choice of default app. So I installed it again.
Because I did not have the original v.10 on it, I installed that first, then installed v11 Beta over it, but it did not reproduce the same problem, so I left the test again.
I already decided to stay with v.10. Not only the newe vesion is problematic because of not being able to start minimized (I do that too, by using a shortcut to the exe with setting start minimized) but it's seems to me being a lot slower in start and response.