windows issue with h.264 videos and LAV filter

Hello,
I am using the latest LAV filers to play mp4/h.264 videos (Intel QSV H.264 codec) with directShow on Windows 8.1 and 10. I am not using a commercial video player. It is part of a custom program, which uses the directShow API. Usually this works fine without any issues.
But from time to time there is a windows 8.1 and 10 machine, where my videos can't be played with the error message "could not create movie reference". The videoscreen just keeps black. This message is the common message, if there is no mp4 filter on the machine. But in my case the setup of LAV was successful and I also tried the ffdShow filters on those problem machines without success, so I don't think it is a matter of LAV, but perhaps of some missing system requirement or some incompatibility.
Has anybody ever experienced this issue or does anybody know, what to check for or which system requirements the LAV filter needs?
Thanks for any hint
Tiemo

If the codec pack installs, then your system meets the requirements.

You can test playback with the GraphStudioNext tool. If it works with that, then it should work with any standard DirectShow application. The problem is most likely in the player that you are using. I searched for that specific error message and found one result that suggests to run the application as an administrator (right-click > run as admin).

Please use DXVA2 copyback instead of Intel QuickSync.

Hi Admin,
thanks for your suggestions.
the general system requirements are obviously met. I thought if there perhaps are any "hidden" or seldom used system options or flags, which can be offset (like e.g. in former times hardware acceleration).
I tested and the graphstudionext can play the video on those machines. On the other hand my player plays the same videos on 99% of the machines fine also. So there must be an unhealthy combination of system requirements and my player and those special machines.
Next time I will go with DXVA2, but right now I have to solve the problem with these existing videos, which are out in the market.

Gather this info on the machines that have the problem:
Codec Tweak Tool > Generate Log

I suspect the problem is unrelated to codecs, but rather with accessing files. Perhaps a permissions issues. Or the application doesn't support Unicode filenames.

Hi,
I've made such a log on one of those machines (here is a logfile), but I don't find anything obvious. For me it looks like the log on my machines, where I don't have any problems. Perhaps you will notice anything wrong? I will ask for the video path name on the customer machines, but I'm almost sure, they are UTF-8 compatible.
I will be off my office for two weeks now, but I will resume afterwords
Thank you for your ideas!
Tiemo

I see the problem. That system is missing a lot of 32-bit filters. That is usually caused by some bad program that accidentally deleted some registry keys.

You can fix it this way:
Codec Tweak Tool > Fixes > Re-register base DirectShow filters

The K-Lite codec pack installer is also capable of fixing this when it detect this anomaly.

YOU SAVED MY DAY (Month)!
I have just let my customer try this registry fix and voila, everything is fine and the videos are playing fine! I never would have come to this solution.
Thank you so much for taking your time and your expertise!
Tiemo