Avidemux crashing for no obvious reason

Hi. I've used a video editor called avidemux 2.5 (portable) for a long time with no problems although I do also have the 2.6 version (also portable) for the odd file that 2.5 doesn't like. Yesterday, I used 2.5 to edit some scenes from a clip then, deciding the volume was too loud, loaded the new file so as to reduce it by a few Db. It wouldn't load, saying “a problem has caused avidemux to stop working”. And that's now the case for every video I try to open with 2.5. I downloaded a clean copy of 2.5 but it crashes too. Version 2.6 still works, however. I've ran ccleaner and malwarebytes. Can anyone suggest what the problem (and cure) could be? My grateful thanks to anyone who can assist.

Update... At the same time as avidemux started crashing, WMP was repeating a video every time I played it and I was saving that problem for later. Turns out I had accidentally hit the 'repeat' button and now that I've unclicked it, avidemux is back to normal. I believe both programs use the same 'engine' so I must assume that avidemux doesn't like WMP being on 'repeat'.