I'm testing the hell out of this now and it works. So, this MIGHT be it. I'm not getting too excited just yet.

no, it's not an external disk, it's inside of the PC.

So far I suppose it works OK. When I changed that stuff in registry and rebooted, Windows 10 indexed everything anew and now I think it's OK....

I THINK I might have solved it, by doing this - got it from here: Search Index Broken, Rebuilding won't help - Windows 7 Help Forums.
It might be too early to surely say, but so far so good. Will...

I can't believe how it just doesn't recognize that I've deleted the files. When I search with Cortana, the results are there - but I deleted them. When I click them, nothing happens - they're...

I used the term "custom", since all other folders are part of the windows (i.e. offline files, user, start menu folders). I have another hard drive for music files, and there I have folder named...

OK I have some interesting developments!!!

Although I have my custom music folder set to be indexed, when I paste something in there, nothing happens.
HOWEVER, when I paste mp3s to ANY OTHER...

System permission - i found this when i googled my issues before and I have set like it should be.

The observing indexing idea is a good one and I've noticed that CPU is between 0 and 1%, and when...

Thanks again. Every setting is as you've mentioned: mp3 is checked, index properties only is selected.

OK now it didn't work again... so what I did, I went to the "indexing options", selected "modify" then looked for the newly added folder. It was there - checked - as if it was already indexed. Then...

unfortunately, I did that already before joining this forum - reinstalled Groove Music via powershell, also did a refresh (Groove Music Library Refresh : Surface). In all fairness, it behaves weird:...

OK, done. It works. I created a file named "test2.txt" and placed it in some folder that is not being indexed - Cortana doesn't find it. Then I place it in that folder where I store my mp3s and...

thanks for your response!

Yes, the folder where I copy mp3s is being watched. If I do index rebuild, I immediately see the added folders in Groove Music, otherwise I don't.

I'm afraid I don't...

Groove Music - the default music app in windows 10 is behaving a bit weird lately.
So, the symptoms are as follows: when I add a series of mp3s in my folder, which is set as default music location...