I am running 12.16 x64 and all has been good 
Now I tried to update to 12.17 and get an error message telling me that the following registry value could not be deleted: 0|Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Compatibility Assistant\Persisted{Resources}Opera.exe
Error-Code: 40
Actually there is no such entry (in HKCU) and I can neither reinstall, update nor uninstall Opera.
Always the same error.
Who can help?
Thanks!