Hi the_fuzz_2000,

Sorry to hear you're having sync issues with your passwords, It seems that AVG has had issues with Firefox issues in the past.

You can follow this link to follow the steps to update and download the AVG extension here : Fix passwords disappearing due to AVG security software {link} or follow the steps below pulled from the article.

Make sure your AVG is up-to-date by following these steps :

1 Double-click the AVG icon on your desktop to open the application.

2 Click the Refresh icon next to Virus definition in the bottom-right corner of the main AVG Antivirus screen.

3 Wait while AVG checks for Virus definition updates.

4 When the update is complete, you see Virus definitions are up to date.

5 If you are asked to restart your computer, click Restart Now to reboot immediately.

You can now recover logins and passwords with AVG add-on support.

AVG add-on support for password restoration : Password Restore for AVG Internet Security {link}

You can also Back up your profile from time to time : Backing up your profile {link}

Hope this helps

Do you have a logins.json.corrupt file in the profile folder ?

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I found the logins.json. It said it was corrupted, so I renamed it back to .json and it worked. Probably a temporary solution, but at least it works.