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