Hi Kirk,
Images are on the C: drive (laptop).
I had hidden the .xmp files in WIN10, and have put the on "show them again", but the .xmp file is not changing. In the 'grid' overview in PM, I can give a star to the image, it shows for a second, and then disappears.. In the preview (where the large images appear), it doesn't register at all it seems.
When taking one "0" and imported it into LR, I could give it one star there, and it remembers, although it seems it wasn't transferred to PM. Other images, which I had first imported into LR (having a 1*) and deciding I wanted to delete, I gave a 0* in PM, which registered, but then wasn't carried over to LR.
I really have no clue what is going on and why it is not working...
BTW: I have successfully culled other images (in another folder on my laptop, 2 days ago), after already having had issues with this folder.
In LR, I have also tried "Metadata" ==> "Read Metadata from file", but that didn't do anything either. I also noticed that images I have deleted yesterday via PM, only got rid of the RAW (.CR2 files), and not the adjoining .xmp sidecar file (maybe because I had the .xmp files hidden in the explorer window?).