Opus freezes with filmstrip

I am testing out opus and experienced this issue: when choosing filmstrip view, opus started to play video in folder, and opus did not respond anymore. Even after a forced close down, the sound of the video kept playing on and I had to restart my PC.

Also: I noticed opus uses lots of processor power, like 80% processor with things like making thumbnails, explorer newer gets above 40 - 50%. I would like to see it lower to prevent noise of my PC cooling fans.

That sounds like an issue with your video codecs/splitters. There are some suggestions here: HOW TO: Enable/fix playback of various media formats in Opus

Telling Opus to only use one thread for thumbnails (via Preferences / Lister Display Modes) may reduce the CPU usage (while making thumbnails take longer to generate).

thanks for the fast reply.
After restarting the PC, and trying again, the video did work. So far so good.

But now I have another issue: when installing, I choose opus to start another program when double clicking on pictures. That did work, until after the restart. Now the image viewer of opus is used. I will try to change that, but I hope opus does not go back to its own viewer after restarting the PC every time.

to follow up on that:

when I go to file/open with/choose default program

the program I want pictures to open with is already selected (incl. the option always open).
So why does opus open pictures with the internal viewer after double clicking?

Preferences / File Operations / Double-click on Files / Use internal picture viewer for...