It seems the problem came from 0Patch software. After removing it MceBuddy running ok now.
Everything working great when converting my wtv (wmc) files using 5.2.1 until today. Tried to converted using same profile that I have been using for a couple of years. Upgraded to 5.2.3 with the same results. Re-re muxing of audio. Tried different profiles same problem. Tried several wtv files and mkv files the the same problem. I tried turning the disable remux option on. The conversion died about 40 seconds into the run. I can provide you with logs just let me know which files you would like. Thanks…
Here is the log file working several days ago.