I am using Thunderbird, and store my local mail folders on NAS.
Suddenly for no apparent reason some (and only some) of them have changed permission from 777 to 600.
Thunderbird files are fine and not corrupted (I can access them via Windows PC OK), but not accesible in Elementary OS:
Access to the file was denied The file at mailbox:///run/user/1000/doc/16212a0c/Local Folders/abcd-efgx?number=739367 is not readable. It may have been removed, moved, or file permissions may be preventing access.
What could possibly cause this and what is the remedy, please?
(I am using elementary OS 5.1.7 Hera)
I have worked out how to change permissions in elementary OS (open Files in new window as Administrator) and can change one file at a time, but two questions remain:
what has caused it?
how do I change permissions to a whole bunch of files rather than one at a time?