Can't write FLAC Tags to file

I have downloaded a set of 30 files from Qobuz. Most are fine but on three or four, I cannot amend the FLAC tags because MP3Tag tells me the file cannot be accessed. So fare I have:
(1) Checked file ownership - all OK and consistent with other files in set
(2) Tried to rewrite tags with foobar, dbpoweramp - same problem
(3) Tried MP3Tag from Explorer context menu - same result
(4) Checked for stray characters in filename - no luck

I am stuck. Any further suggestions?
Bill

Rename them with a very short path.

Also, I've seen reported elsewhere some odd problems with Quobuz flac downloads. You can easily convert these from FLAC to FLAC (since they are lossless). this is reported to solve the odd problems encountered with some Quobuz downloads.

I have been searching for a solution to the same problem" Can't write FLAC tags to file".

Then I found the above. I moved my files directly to C:

Issues went away. Thanks for this great advice!