HELP: ACDSee Pro 10 doesn't work anymore

[kaisa]

I uninstalled in different ways and reinstalled, sometimes restarting PC in between. I instantly get a "encountered a system error and will close" error on starting the APP. Frustrating.
I prefer ACDSee Pro 10 as it is faster in some areas and I have two licenses. Newer version don't have much improvement in existing functions. just some new stuff I don't really need and is slower in some crucial areas like browsing and opening develop mode.

I am an IT guy and at my wits end and tried:
- Photo Studio Professional 2021 works with no problems as a trial.
- I removed user/local/AppData/ACD Systems folder
- I removed registry key HKEY-Local Machine/Software/ACD Systems. (but many key left in registry after uninstall)
- I removed Program Files/ACD Systems/ACDSee Pro/10.0
- I tried another user on my system which hasn't used ACDSee Pro before.

I had fiddled around with disabling startup apps and removing them in registry to avoid the background helper programs to run. Maybe something has cause that problem. But strage that it wouldn't be fixed during installation.
Any log I can check to see what problem it is causing problems?

[Xyzzy]

Try r_acd utility to remove leftovers after deinstallation.
Try Process Monitor to see where it fails (useful if there is some specific OS item that triggers the crash).

[albertob]

Try r_acd utility to remove leftovers after deinstallation.
Try Process Monitor to see where it fails (useful if there is some specific OS item that triggers the crash).

same issue with both 10 pro and pro 2021, sunddntly they stopped working, they start for a sec appear then crush. I've been using acdsee for ages now without particulars toruble .
hi , can you explain me what is a Process monitor?
thanks