Hi Kate, When a folder is deleted, it should go to the Trash folder. Maybe you don't need to restore a backup. ☺️ Is the Kathy folder in the Trash folder? If so, just drag the folder back to where it was.

If the folder is really gone, restoring a single folder is really easy.

1. Create sub-folders in the Local Folders account with the same name as the folder you want to import.
2. Go to [=] > Help > Troubleshooting Information, then click on Open Folder and close Thunderbird. That will open your profile folder.
3. In your profile, go to the \Mail\ folder, then the \Local Folders\ folder.
4. There should be files for the folder you want to import that you created in step 1. In this step replace the those files with the ones from your backup. They should have the same names.
5. Open Thunderbird. In your Local Folders account, you should see folder from your backup. At that point, you can drag and drop the messages between folders within Thunderbird.

Trash had already been emptied by the time the bat signal was sent up.

But you were right, your solution was easy with those instructions. I wouldn't have been able to figure that out on my own.

My elderly Mom is relieved her folders are back in place (it turns out it was the whole FAMILY folder she accidentally deleted) and she has promised no more late night email folder management!

Thanks for your help, Chris.

Thank you so much; I lost a folder, was happy to have a backup of my thunderbird files, but did not know what to do with these files. Following Chris' suggestion I created within Thunderbird a folder SomeName in the Local Folders account. In step 4 of Chris' solution I was confused because I only saw the files SomeName and SomeName.msf but no folder with that name. What worked was to just copy that folder from my file backup to the Mail\Local Folder. So I had to copy two files + one folder from my backup. All of these with SomeName.

It also turned out that it is not necessary to first create a folder with SomeName in Thunderbird. I could just copy the two files and the folder with SomeName from my backup to Mail\Local Folder. (Close and open Thunderbird to see the changes. ) So in the end it was even easier than suggested.