Local files not playable on desktop, fine on Android phone

[koltregaskes]

Plan

Premium

Country

UK

Device

Desktop PC, Pixel 3 Android phone

Operating System

Windows 10

My Question or Issue

I have reinstalled my Windows 10 OS as well as Spotify on my desktop PC.  I've added my local files to the settings page and now see my local music files but not all are playable.  I know that some might be restricted or not on Spotify but it's odd that the same local files are playable on my Pixel 3 phone.  How is this possible?  They were original from my desktop PC.

Please advise what the issue could be?  It might have been an issue before resintalling Windows that I didn't notice.