First, you should check your sync settings and make sure it's turned on. If it's already on, you can try reinstalling Firefox. You can also remove old authorized devices from your sync account. If none of this works, you might have to manually import the passwords from your phone. I'm Chinese, so please excuse any mistakes in my English. Hope these suggestions can help you.

Thank you for your reply. I think I have found the problem.

I didn't know that there were two Firefox profiles on my computer and it had opened up a rogue profile with no passwords saved. The password problem cured itself when I restarted after a driver update. Once the computer had rebooted and Firefox was opened, there were two profiles and Firefox wanted to know which profile to use. I tried both and one of them had the passwords etc, while the other profile did not.

It seems that when the passwords went missing, it was because Firefox had opened with the rogue profile where no passwords were stored.

Why it opened the other profile and how the other profile came into being is a mystery.

The problem now is that Firefox will not allow the unwanted profile to be deleted.

Does anyone know how to get rid of the unwanted profile that seems to be locked onto something else?

Hi John, Glad to hear you found the root cause! The rogue profile issue is more common than you think. Here's how to completely remove it: Step 1: Use the Official Profile Manager (Safest Way)

Completely close Firefox.  ​ Press Win + R, type firefox.exe -P and hit Enter. This will open the Firefox Profile Manager.  ​ You will see a list of your profiles (like “default - release”, “default” and your rogue one).  ​ Select the unwanted profile and click “Delete Profile...”. If the button is greyed out, it means the profile is in use or locked. Proceed to Step 2. Step 2: Force Unlock and Manual Deletion If Step 1 fails, the profile is likely locked by a process.  ​ Ensure Firefox is fully closed: Open Task Manager (Ctrl + Shift + Esc), end all processes named firefox.exe or GeckoMain.  ​ Manually delete the profile folder: In the Profile Manager, click on the unwanted profile. The “Root Directory” path will be shown (e.g., C:\Users\YourName\AppData\Roaming\Mozilla\Firefox\Profiles\xxxxxxx.rogue). Copy this path, then close the Profile Manager. Open File Explorer, paste the path into the address bar, and press Enter. Go up one level to the Profiles folder. Rename the rogue profile folder (e.g., add.old at the end). This acts as a backup. Restart Firefox. It should automatically start with the correct profile. If everything works, you can then delete the renamed.old folder. Step 3: How the Rogue Profile Might Have Been Created The most likely causes are: A Firefox update or repair operation sometimes creates fresh profile. You might have accidentally launched Firefox with the -no - remote or -CreateProfile argument. A system restore or migration tool could have duplicated it. Prevention for the Future To avoid launching the wrong profile, set your primary profile as the default in the Profile Manager (firefox.exe -P). You can also create a desktop shortcut that directly launches your desired profile by appending -P "YourProfileName" to the target path. Hope this clears up the mystery and helps you clean up completely!