Further info, just updated to 60.7.2 but no joy. Another thing, when I looked the folder had been cut down to 60 MB. I had saved a copy and replaced the original 500MB folder but it gets cut down to 60MB again. So confusing!

re : I had saved a copy and replaced the original 500MB folder but it gets cut down to 60MB again.

Do you exit Thunderbird first before accessing profile folder and making changes? Changes will not work if Thunderbird is running.

Are you putting the that folder back into an imap or pop mail account? You cannot put it back into an imap mail account because when you start Thunderbird, the folder synchonises to show what is on server.

If pop account, do you also delete the *.msf file? If no then delete the corresponding .msf file.

If you have done the above but still no joy: Open a copy of the backup 500MB mbox file using a program like Notepad or Notepad++ or similiar text editor program. Use 'Edit' > 'Find' Starting at the top of document look for this line: X-Mozilla-Status: It may have various numbers eg: 0001, 0009 etc

Make sure each X-Mozilla-Status: has the number 0001

edit the number as required working down through the document. Save the file. Now put copy of that saved file into the correct pop mail account or Local Folders mail account. delete the appropriate .msf file start Thunderbird.

Hi Toad

Thanks for your input. To answer your questions:

Yes I closed Thunderbird before accessing the folder. It is POP I did delete the msf file

I did as you suggested and there were a number of non 0001 instances. I changed them all, put the file in the correct place after delting the old one and msf but it does exactly the same.

I did notice several X-Mozilla-Status2: instances - do these need to be changed also?

Cheers, Ron