Re-installing Thunderbird on Windows 11

If Windows was a fresh install, wiping and reloading, then all data on PC is lost. If you have a backup, we can assist in restoring it. If Thunderbird has not yet been reinstalled, you can verify absence of data with these steps:

1. enter %appdata% in search box on windows tool bar and press enter key
2. that should open FIle Explorer in the appdata\roaming folder
3. if there is a Thunderbird folder, let us know and we will assist, I doubt it is there if full Windows reinstall, but I show the option to check anyway.

Tip: If the account was IMAP, you have lost nothing. Just reinstall thunderbird and set the account up again.

Thanks for your prompt reply. I did reinstall Thunderbird and found that I had retained the contents of the Inbox (plus some emails from last year which had been in an archive file). My archived files also show up as folders but none of them have any contents except for the one named 2008; some of them as sub-folders of the Archives folder but some not. However I do have a file on an external hard drive called Thunderbird Profile from 2025. Can I use that file?

If you did not format the disk when reinstalling there is a chance your profile was saved in c:\windows.old.

Thanks but unfortunately it doesn't show up there.

Assuming a folder named Thunderbird, and assuming it isn't corrupted, try this:

1. install thunderbird from thunderbird.net.
2. start once and then exit
3. enter %appdata% in serch window and press enter
4. window should open at appdata\roaming
5. delete the thunderbird folder and then replace with your backup thunderbird folder
6. start thunderbird

Didn't work but thanks just the same.

If you explain what didn't work, we may be able to help salvage whatever is there. any error message? can you do a screenshot of what your thunderbird folder contains in File Explorer?

Thanks for your interest. As it stands now, here are the contents of my Thunderbird folder and of the Backup Profile folder from the external hard drive. Hope you can make sense of all this. jz

The attached screenshot is the place to focus. That folder of 'Thunderbird Profile' is where your data are. The screenshot is of part of one profile (begins with ttq6zys1.default), but there may be others is the 'Thunderbird Profile' folder. Look there to see if there are other profiles. If so, look at the dates of each to see which is the most current. Also, in that 'Thunderbird Profile' folder there may be a file called profiles.ini. If so, it is a simple text file you can open with Notepad. It will have a PATH statement that identifies the active profile.

Now, just to be sure, click the Mail folder in that profile and you should see a folder that has the name of your POP account.

Post a screenshot of the contents of that profile.

Next, do these steps:

1. start thunderbird (install if not already done)
2. click 'help>troubleshootinginformation
3. scroll to 'profile folder' and click 'open folder'
4. exit thunderbird
5. you are now in the profile. DELETE everything here
6. now, paste the full content of that backup profile here
7. restart thunderbird and let me know.