How to backup Thunder Mail
1. Open up Start Menu or Windows Explorer and browse to %appdata%.
The full path will be C:\Users\username\Appdata\Roaming on most Windows installations.
2. Scroll down and find the Thunderbird
3. If you don’t see the AppData folder, make sure you have Show Hidden Files, Folder, and Drives unchecked in Folder Options.
4. Right-click the Thunderbird Folder.
5. Wait a few seconds for your Thunderbird folder.
Your original folder will remain exactly where it was.
6. Now you have Thunderbird completely in your computer memory right click on free space and paste.
This should give you a folder "Thunderbird - Copy"
How to recover Thunder Mail
1. Open up Start Menu or Windows Explorer and browse to %appdata%.
The full path will be C:\Users\username\Appdata\Roaming (on most Windows installations.)
2. Scroll down and see if the "Thunderbird" folder is there.
3. If the folder exists right click on the folder and rename it "Thunderbird-old"
4. Right click on the "Thunderbird - Copy" folder and select copy
5. On the same window right click again but on empty white space and paste
6. Rename the folder "Thunderbird - Copy Copy" to "Thunderbird" by right clicking on the folder and clicking on rename.
Your Thunderbird should be operational.
Disclaimer: This guide is given in good faith with out warranty and liability please use at your own risk.