https://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I'm Not an expert but you can Re-build the New Profile with Old Data per above (adding Key Folders-Files from Old to New) - OR - in Profiles Folder I'd try Re-Naming the New Profile (ADD .old to the .default to render it Temp Unusable) and copy your old .default Profile to that Profile Folder. See what happens. If No Success, remove old Profile and remove - .old - from name to restore new Profile use.

I regularly COPY the entire Profile to Bkup drives and use Hekasoft Bkup-Restore to do same (a few clks and 5-7 seconds = Bkup I've used to restore FF). Keep 2-3 bkups and update ea 2-3 days. https://hekasoft.com/hekasoft-backup-restore/

Hey CraigS26,

Thanks for the reply, but unfortunately the steps you provided do not help my situation since I didn't know that I needed to create a backup of my bookmarks/profile. And since I needed to do a clean reinstall of windows, I no longer have any files of my old profile and also have no way to retrieve them either.

The only profile I can find in the Profile folder is the new profile that was created when I reinstalled Firefox, which is also the one that is currently being used.

Unfortunately this issue happens with lots of people. Sync is not a backup, it's meant to synchronise between different browsers. If you use it on only one device, then reinstall it, you'll most likely lose all your data. Do you have any other devices where the data may be available?

Hey Balázs, I had synced Firefox with my android phone, so maybe my data might be available on there. Do you know how I could check?

Hey Balázs, I had synced Firefox with my android phone, so maybe my data might be available on there. Do you know how I could check?

Hopefully Balázs returns to bail us out BUT .... does FF Sync offer -- Android to Desktop Sync ? -- ... you have nothing to lose with a New desktop Profile being there ..... Just be sure YOU're sure of direction so you don't Sync a Blank desktop bookmarks folder TO YOUR PHONE and wipe it ....

OR, this app allows data transfer from Android to Desktop .... https://www.syncios.com/android/backup-android-bookmarks-to-pc.html#img2

Backup Android Bookmarks to PC

Step 1. Download and install Syncios Data Transfer on your computer firstly before saving bookmarks to pc.

Step 2. Then launch the program and find Backup to PC on the homepage.

Step 3. Connect your Android device to PC and wait for data loading. All of your data will be listed on the middle box. Tick Bookmarks to transfer after data loading and then click on Start Copy to transfer bookmarks to computer.