I have read that a lot of people had this particular issue and I tried fixing it with the tips given but it did not work for me.
My problem: I downloaded the Fire Emblem Three Houses OST from a site for video game OSTs (link) and I wanted to change the tags a little bit (add covers to the files, change the genre, ...). I tried it on all 134 at once and it worked on almost all of them without a problem, but for 12 of them it said "File '-.mp3' cannot be opened for writing". I changed their location to a temporary folder on different drives and locations and tried tagging them one by one but I just would not work. Precisely, for 3 of them the genre, CD number and album can be changed but I cannot add a cover.
I also tried scanning all the files with mp3val and they are all ok and have no errors according to the scan.
Also, I cannot remove or cut the tag (the same error message appears).
I will add a screenshot of the problem and here is a wetransfer link to download one of the not working files (Note: The file works fine, it just will not let me tag them)
Thank you in advance for your help!