Why is Google Play Music app not finding the music files from Micro-SD memory card on my HTC 10?

[Android Central Question]

I transferred Micro-SD memory card from my HTC One to the current HTC 10. It is 64GB card and I have about 28GB of music stored in it. For some reason, apparently the same Google Play Music application that was playing the songs fine in HTC One, does not seem to find any music files on the card in HTC 10.

A few things I have tried:
-refreshing the music library in the app
-clearing the memory cache in the app
-clearing the memory in the app
-removing any .nomedia files from the SD card
-unmounting and re-mounting the SD memory card
-rebooting the phone

I doubt the memory card is corrupted because it works fine in HTC One, and also in this HTC 10 via Settings -> Storage I can see all the music files in the Mobile -> Music folder. Also the picture files in the card are in use as wallpaper on the phone.

Can you please advice, what else should I try?

 

[Rukbat]

You could force the phone to rebuild the media database with media.Re.Scan, just in case.

 

[SanttuPV]

You could force the phone to rebuild the media database with media.Re.Scan, just in case.

Thank you for the tip Rukbat!
Unfortunately it did not solve the problem. I installed the media.Re.Scan app via the link you provided, and did the scan - all the music files on the SD-card were 'discovered' by the scanner. But no change to Google Music Player status; I did another refresh, cleared memory cache etc, yet it still does not find the music files from the SD-card.

Now I have also re-formatted the SD-card in the phone, and then copied all my music from laptop again to the card. Same result - the music files are not visible in the music player library. I also did another media.Re.Scan and player library refresh - no change.

I also tried another music player app I found from the Play Store. Same issue - the app did not find the music files from the SD-card.

One thing that I find strange is that when I go into phone Settings => Apps => Google Play Music, it shows 'Internal shared storage' as storage used. It is not possible to change this setting, as the change-button is grey and not usable. In the Google Play Music app internal settings, I have the external SD card selected as storage location.

Any further instructions on how I could get the music files, that worked so fine in my previous HTC, to work also in this HTC 10, would be much appreciated