A huge thanks to MiPi
For anyone else experiencing similar problems, the problem was caused by a plugin file in_flac.dll Once this was deleted then everything works perfectly

Could you upload me some sample file, that causes such problems? You can use any file sharing service and send me link to PM. Thanks.

I have a few 24 bit FLAC files that don't play properly, or at all. They play OK using VLC and the microsoft music player.
My environment is Win10 with the PC getting files from my server - both in the same location / on the same network - as above they play OK using VLC etc
MM version 4.1.24.1883

The files either
- don't play at all
- start playing, then skip to the next track before completion
- generate an error "Assertion failure (....MediaMonkey\MP#Datab\GeneralDecoder.pas, line 944)"

Help please