Do you have the Thunderbird folder from old PC or just the profile? That is important to give proper instructions. If old PC is available, that would be a plus. For full cleaning, uninstall thunderbird and delete the c:\users\<yourid>\appdata\roaming\thunderbird folder. Do likewise for c:\users\<yourid>\appdata\local\thunderbird. With these gone, there are no remnants left of old accounts. Here are proper steps:

Here is the link for moving a profile in Windows when installed in default location:

https://support.mozilla.org/en-US/kb/moving-thunderbird-data-to-a-new-computer

here is the info in brief steps:

1. ensure thunderbird is NOT running on old machine
2. enter %appdata% in search window on task bar and press Enter key
3. this should open windows file explorer in Appdata\roaming folder
4. highlight the Thunderbird folder and copy to external media
5. ensure thunderbird is installed on second computer and NOT running
6. enter %appdata% in search window on task bar and press Enter key
7. you should be in Appdata\roaming folder , copy&paste the exported Thunderbird folder there. This may prompt to overwrite an existing folder of same name. allow it
8. start thunderbird and all should be there

I do still have Thunderbird untouched on the old computer. Initially I had installed Thunderbird on the new one, set up accounts and used it for a few days then tried to do the file transfer but none of the "old" info showed up. Then I read it should be a clean install, close it right after it's installed then go through the transferring steps. I have deleted Thunderbird and the files you listed (I didn't realize there were 2). I've used the file explorer to look for anything related to Thunderbird. I even emptied the recycle bin and restarted after everything was deleted. Downloaded and installed Thunderbird, expecting it to be clean but all the information from the newer info I setup still remains! Am I still missing something?

I have done everything here at least 6 times now. During the copy process to the new laptop I can see the names of the folders and subfolders that were on the old laptop but when I open Thunderbird after it's done NONE of those folders show up! I see a lot of other threads on here with the same issue but so far I haven't read one where anyone got an answer that fixed anything.

Can you do a screenshot of the folders in exported profile? If IMAP messages are missing, do screenshot of the imapmail\<IMAP account> folder. Do the same for mail\<POP account> folder if POP folders missing. And do same for mail\Local Folders if local folders are missing. Then, do the same from within Thunderbird. You can get to profile folder with these steps: - click help>troubleshootinginformation - scroll to 'profile folder' and click 'open folder' - then exit thunderbird. you are now in the profile. create the same screenshots here and post all of them. That should show clearly what was in the exported profile and what is now missing. With that knowledge, I can assist in getting the missing folders back. Thank you

Ok, working more extensively on it again yesterday I think I've determined that the actual problem is the transference of folders and subfolders (there were a lot!), most specifically on a comcast mail account. I only had those folders in the TB version, not on the Comcast email site so maybe that's why they don't show up in the "subscribe" list? My next action was going to be to try and transfer each folder individually and see if I can add them onto the new install. Do you know if this is possible or can you make a more reasonable suggestion? I've spent many hours with this and just want to get back to using TB again! TY

You have never shared details, so it's difficult to be specific. Your problem should normally be a simple one. IF the account is IMAP, then any folders within the account would be on the server and displayed in the subscribe list. IF not, then they would be unique folders you created in the POP account (I say that because POP defaults to inbox, sent, trash). I would feel more confident in a suggestion if I saw screenshots of the folders but, in general, yes, you can copy the folders from one profile to another while thunderbird is not running. Ignore the .msf files. My comment applies only to folders in Local Folders and unique folders within a POP account.