I think I'm experiencing a similar problem (and so is this guy
I keep my thunderbird profile on a USB stick (FAT32 formatted) so I can use it across computers, but I only use the linux version of thunderbird (icedove 3.1.16). Everything worked fine for years until about a month ago, without any intentional changes to the system.
Here's what happens:
As soon as the first mail is downloaded (and all messages are deleted from the server
), the filesystem appears as read only to the user and Thunderbird says "This message may contain a virus or there is not enough disk space. Skip this message?". It doesn't make a difference what I click, the mail is completely lost.
ls -l still reports the user as owner of all files on the fs and gives permissions as "rwxr-xr-x", but trying to write to it results in the error "Read-only file system"
The user can still unmount the fs (e.g. via the context menu in thunar), and after remounting it, everything is fine again (until thunderbird is started again).
As root, the file system can be normally accessed and mount doesn't say anything about read-only.
I'd really appreciate any ideas on what could cause this, because it is extremely annoying.