I understand how stressful and frustrating this experience has been, especially after you’ve had successful resets on your Windows 10 PC.
The key difference could be due to how Windows 11 handles resetting compared to Windows 10. In Windows 11, even though the "Keep my files" option is chosen, some apps and settings may still be affected, especially if any issues occur during the process. The slowness and interruptions you experienced might indicate the reset wasn’t as smooth as it should have been, which can lead to partial loss of settings like bookmarks and saved passwords.
If the bookmark manager shortcut didn’t work in Firefox, try this:
Open Firefox.
Click on the hamburger menu (three horizontal lines) at the top right.
Click Bookmarks → Manage Bookmarks to access the bookmarks manager.
If it's still not possible, lets check manually.
Locate Your Old Profile Folder:
Press Windows + R, type %APPDATA%\Mozilla\Firefox\Profiles, and press Enter.
Check if there are multiple folders here. Each folder corresponds to a different profile.
If you find an old profile, you can copy it to a backup folder.
Restore the Profile:
Open Firefox.
Type about into the address bar and press Enter.
You’ll see a list of profiles. You can try creating a new profile and linking it to the old profile folder (the one you found in %APPDATA%\Mozilla\Firefox\Profiles).
For Thunderbird:
Locate Thunderbird Profile Folder:
Press Windows + R, type %APPDATA%\Thunderbird\Profiles, and press Enter.
Look for folders in this location that may be your old profile.
Restore the Profile:
Open Thunderbird.
Go to Help → More Troubleshooting Information → Profile Folder → Open Folder.
Copy and paste the old profile folder contents (if you found it) into this new profile folder.
Please let me know if this works for you. I'll do my best to respond as soon as possible.