So I have investigated the problem by myself.
I have one video file which is in drive root. Xnview crashes on it all the time while trying to create file thumb.
FFmpeg says file is valid and correct. Also tryed to verify it and reverse to bunch of pics. But I don't think so. It's like it corrupted somehow and causes parser to die in pain

Can u check it and make exception handling in similar situation or etc?
https://drive.google.com/file/d/1eOEBzo ... sp=sharing
1. Move file i.e. R:\1\file.mp4
2. Navigate from xnview to R:\1\
3. Get instant crash if video thumbs are enabled
Btw, I have tryed to force program to work on default settings by fully removing settings and cache dir. Still crashes.