Have you considered updating the firmware to see if it helps?

Thanks. Handy to know.

Is the conversion reversible? i.e. put it back to SDM?

But a set of batteries must be worth a try. Four AA batteries will have other uses even if it doesn't resolve the problem they were bought for! It won't be money wasted.

Sadly that would seem to be the issue.
Someone on the USA forum resolved it by using different batteries (Eneloops.)
https://www.pentaxforums.com/forums/58-troubleshooting-beginner-help/342828-pent...
Got to be worth a try?
That used to resolve issues with the earlier Pentax DSLRs that wouldn't even turn on.

That's really just a photo organiser. Can't you simply move your photos to folders using Windows Explorer without a dedicated program? They can be viewed using Windows Photo viewer. No additional software required. I find using dedicated organiser programs for the task ties you in to their systems, then eventually the inevitable happens as you just experienced.
Do you keep backups of photos on an external drive, if not, why not? If they are valuable to you you should!

If you then wish to catalogue your photo folders Thumbsplus is pretty good for that:
https://thumbsplus1.software.informer.com/7.0/
*(That's an old version now offered for free)

Irfanview also has an organiser besides being a useful image processing program.
https://www.irfanview.com/
(again good and free!)

I use both, regularly.

Just to say, try and own your photos and not let software do it for you!

What's the issue with your K-50?

Media Impression 2.0 isn't compatible with Windows 10.
As to those lost files, what was your 'F' drive? If it's the camera SD card your card reader may not be compatible with Widows 10 either, or may simply require an updated driver. Can you find the photo files using Windows Explorer?

The central lighthouse in that shot strangely works for me. Good capture.

I wouldn't recommend putting any of your Pentax's on the back burner of your new cooker when you get it!