Copy the large file named Inbox, that has no extension (it's an mbox file), from the old profile to Mail/Local Folders in the new profile, with TB closed. Rename the file if necessary, then restart TB and see if the folder appears under Local Folders in the Folder Pane.

Hmm my previous reply did not appear. I also need the archives section since many files are compressed there so I copied it as well. On checking local folders the ones I added are present but show 0 e-mails. I should note if the folder is selected before reopening Thunderbird I get a cursor with an hourglass.

So, you copied the mbox files, they appear under Local Folders when TB restarts, but the contents are empty? Is there a security/antivirus scanning the profile folder? Make sure you only copied the mbox, not the .msf with the same name, as it is recreated on restart.

I copied the inbox folder and renamed it on purpose as directed. I did not touch the .MSF file there. The inbox shows 6.5 gig of e-mails since we get videos from other people so the file acts like it is all there but once in Thunderbird there is nothing but the hourglass going. I have disabled my Antivirus as well.

Check Activity Monitor under Tools. A 6.5GB folder may take a while to index (create the .msf file), which would explain the hourglass. The global search index would also regenerate, if global search is enabled.

Nothing showing in the activity monitor besides my normal 3 e-mails. I cleared it and restarted just to see what would show and still only the 3 e-mails I have. I do understand the file being large could take time to rebuild so am I correct to think that leaving Thunderbird open will let it work?

Yes, I think I'd leave TB open for a while and see if the folders eventually appear. If you had tried the method with a small mbox file, with just a few hundred messages, I think you'd see that it works.

I thank you for trying to help. My parents are beside themselves about this. My computer is allot more powerful so I figured on trying it at my place. I really hope this works and will be backed up ASAP if it does.

Once up and running, I would advise you save those videos to a folder eg: 'Documents' or 'Videos' on their computer - not in Thunderbird. I would also advise you show them how to organise incoming mail into suitably named folders because it would seem, at the moment, you have absolutely everything saved in just one single text file - which has appended one email after the other in the order downloaded into one file, which is a bit risky. Smaller files are easier to access.

I admit we are used to Outlook receiving e-mails that makes them all local stored. The e-mails of importance were moved into sub folders under the Inbox but not on the local level at the bottom of Thunderbird. I set my computer to never sleep for the last 72 running on only a 27k file folder with the specific e-mails that we needed to recover and there is no change. There is no activity on the manager but the hourglass spinning on that folder. Since nothing has changed it looks like they are all lost.

Is there a program that can examine the file and preform a repair or make it readable other then Thunderbird to consider? It is odd that the profiles show the files exist and size are not empty files but on Thunderbird act like they are empty files.