As of yesterday, I can no longer start GOG Galaxy. Windows gives the error message that it "cannot find <install location>\GOG Galaxy\GalaxyClient.exe".

I've tried uninstalling, reinstalling the newest version and restarting PC; it still gives the same error. Does anyone know what's causing this or how it can be fixed?

Yes

May be too obvious but is the File there? Is the general directory existing?
If the directory exists but the .exe is missing i would guess on antivirus program that got hungry.
If the whole directory is missing either the install location is wrong or the install got blocked/went totally wrong.
In that case i'd start a search for 'Galaxy' over all drives, maybe it's just somewhere else and the link is outdated.

If there is no trace to be found try to install it again and either open the location in the explorer to see if something gets written there or as an advanced possibility get the microsoft sysinterals suite, start procmon and watch with that what is happening.

same issue, after updating Windows 11.

EA App and GOG has issues.

Rockstar games launcher - help reinstallation.
EPIC, Steam and Battle.net works normally

....
Okay So I solved the problem and I want to post it here if anyone else might have the same problem with any kind of .exe

https://superuser.com/questions/589030/windows-cannot-find-exe-some-apps-only


The first top answer has it all in it. I went to the registry (Windows+R --> regedit)

and went to the folder

HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Image File Execution Options

Right there I found a subkey for the galaxy client that was pointing to a program called CCleaner that I've used after updating windows 11 After chaning the subkey to correct path the galaxy client installed without any errors and started right up. Same with EA Play