Sounds like Thunderbird does not have the necessary read write privileges to MSF files in that drive. Is you copy of Thunderbird actually installed? Is this the same if you restart from the help menu with troubleshooting mode?

You could just delete the relevant MSF files from the profile folder and they will be rebuilt when the application starts and the folder is accessed. But that you have the issue in the first place makes me wonder what is locking access to the relevant drive location.

Thanks for your reply Matt!

Over the last couple of weeks a couple of things have occurred with regard to this issue:

1) I discovered that the profile is in maildir format

2) The overlapping header issue stopped occurring

I converted this profile to maildir a couple of years ago when support was first announced. Once I discovered that thunderbird maildir is not compatible with other s/w standard maildir, my reason for this conversion was no longer valid.

I'm not sure why the header error stopped 8-/ I stopped and re-started thunderbird a number of times before filing this issue ticket, and the error persisted. But over the next week or so , the error stopped occurring.

There are a couple of residual questions:

A - Should I convert the profile back to MBOX format? Howto?

B - Should the "Repair Folder" button be disabled fora ll maildir profiles?

C - Does deleting the MSF files work in correcting maildir synchronization issues?

Thanks again!

johnea 2024-03-13

Lets start with the really obvious. Maildir can be enabled, but it is not considered stable. See https://support.mozilla.org/en-US/kb/maildir-thunderbird

I do not have time to go through the bugs looking for your before suggesting you file a bug, but there is a link in the article for open bugs in the maildir like implementation (it was never advertised be the developer that did the implementation as maildir) if you can't find yours listed, you might think about filing a bug.