The emails do not delete using Outlook but my boss is unwilling to switch to this program before his trip away.

I would hazard a guess the problem is between the keyboard and the management chair. inadvertently deleted and purged 40 thousand emails.

I think the best approach would be to actually remove the account from Thunderbird. Thunderbird will be syncing the records it has. The simplest way is get rid of that synchronization and start again.

So. in account settings. Right click the account in the folder tree and select settings Use the account actions button to remove the account.

On the help menu, select the troubleshooting information. Click the show folder button for the profile folder. Close Thunderbird. Open the IMAPMail folder in the explorer window that opened. locate the folder named for the exchange server. Delete it.

Now restart Thunderbird and recreate the account. Everything should sync including your recovered folder.

If you are in the least bit squeamish move the mail folder somewhere else instead of deleting it.

Thanks Matt and I definitely agree with the first part of your reply. This is the most stressful time in my life!!

The problem seems to be thunderbird has marked them so it just removes them again.

I think I have managed a workaround in the mean time of posting the original message.

I unsubscribed the restoration folder from his thunderbird profiles he has on his pc and laptop (He refuses point blank to move to Outlook) so could restore the 44,000 emails. I then exported them as a pst in outlook.

Imported the pst into a new outlook account. Now I am importing into the local folders of thunderbird. 45 minutes in and it's still importing so fingers crossed it's working as I ran a test of this method on about 5 emails and it worked. So fingers crossed this will work so I can begin rebuilding his database.

Thank you for the help on this Matt it's very much appreciated.