It's possible that v53 is accessing the wrong profile. Using v52, Type about:profiles<enter> in the address bar. How many profiles are listed? How many should be there?

Write down the name of the current profile.

Now start v53 and repeat the above. Is it the same profile?

In the event that the passwords information is lost, you should record all information in a separate text file somewhere else on your hard drive, or written down. You can easily copy and paste if you need to do so. If you are concerned about someone else looking at that file, you can compress it using a password.

Separate Issue; Make sure your player is up to date. Flash Player Version: 25.0.0.148

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download. <Windows Only>

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

Same profile (default) on Firefox 53 and 52 (in this moment I'm using 51 because I have the installation pack ready to install, but it has the same behaviour). Only one profile installed, same folder and same name.

I'd prefer to avoid to copy all my links and passwords manually. I hope this compatibility problem should solved.

Thanks for the suggestion about Flash. I know and for the moment I take the plugin blocked.

I found a similar problem posted here: https://support.mozilla.org/en-US/questions/1158059

I'm not alone...

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Do you have non ASCII (Unicode or accented) characters in the MP?

You can also check permissions and owner ship of the logins.json and key3.db files.

Same problem in Windows Safe Mode. No special characters in MP. I checked permissions and ownership of the two files but nothing strange... they seems standard files. Upgrading and downgrading Firefox maintain these files and with old version I can access to passwords, with new 53 version the saved password table seems empty. If I try to enable MP from checkbox an error occurs, as described in the other post. It seems Firefox 53 recognizes that something about MP and passwords is present but it isn't able to manage it.

See also: /questions/1157769 "Unable to change Master Password" message appears every time I try to create one!

Do you see any error messages in the Browser Console about the Password Manager?

• https://developer.mozilla.org/Tools/Browser_Console

Hi all, I solved the problem following the solution described in the following post: https://support.mozilla.org/en-US/questions/1157892

Just renaming the secmod.db file in the user profile folder and the MP and saved password works again.

Btw, In the browser console no error are reported.

That was very good work. Well done.