Problem adding FFDecode filter with limited user account, K-Lite Basic Windows

K-Lite is installed while in admin mode. I'm getting an 80004002 error trying to add ffdshow filters to a filtergraph when running with a limited account.

The issue is that there are no registry keys at HKEY_CURRENT_USER/Software/GNU for the limited account like there is for the admin account. If I copy the keys from HKEY_CURRENT_USER/Software/GNU from the admin to the limited account the issue goes away.

I'm trying to figure out what process creates the initial registry keys for an account, or is that only done by the installer?

Those registry keys get created by ffdshow itself on first run when they do not exist yet.

What kind of audio/video are you trying to decode? How are you building the filter graph?

It's failing in CoCreateInstance trying to create the ffdecode filter, so I never even got to add it to the filtergraph.

Running CodecTweakTool and doing a reset settings also fixes the issue.

I have figured out why it happens. ffdshow enables its whitelist by default and your application is not on it.
It works on admin account and when resetting with CTT because there is an option in the codec pack to enable/disable the whitelist.
Unfortunately it is impossible for the installer to access settings on other user accounts. So you will have to work around this problem in your application. You could try creating the registry value "isWhitelist" with value 0 in HKCU.
Another solution would be to use LAV Audio and Video decoder instead of ffdshow.