update: the password files are ok, if I move only those files they are read and written correctly, so there is other sort of incompatibility between OS that affect the password managment..

I would add that the profile I moved is the basic one, without any plugin or extension installed, maybe the problem is not the profile but the executable itself?

Do not copy pkcs11.txt and a possible secmode.db. Best is to only copy database (SQLite and JSON) files you really need because some file can store path/file information that isn't compatible. The pkcs11.txt and prefs.js are examples of files that you shouldn't copy. Some folders may cause issues as well.

cor-el said

Do not copy pkcs11.txt and a possible secmode.db. Best is to only copy database (SQLite and JSON) files you really need because some file can store path/file information that isn't compatible. The pkcs11.txt and prefs.js are examples of files that you shouldn't copy. Some folders may cause issues as well.

Thanks for your reply, it solved the problem.

The only file that proved to be incompatible was the pointless "pkcs11.txt".

If somebody copy own profiles from Windows to Linux Firefox won't read/write passwrod due to that file, it is a bug that must be solved.

Apparently no other files give issues, what else problems can cause other files like pref.js?

This issue should be highlighted in the main help pages of Firefox.

Should we report this problem as a bug?

Did you check the content of pkcs11.txt ?

Then you will likely see that it contains a Windows style path to the current profile and not a valid Linux path. The Password Manager runs in a separate thread and need to be able to access the profile folder and with a wrong or invalid path this isn't possible. Copying a profile or renaming a profile isn't supported. You may be lucky if it works without problems, but it is not a bug if it doesn't work.

I understand, but I didn't setup that path, it is based on user directory according to the OS rules, so when Firefox finds a path belonging to another OS can take an action to solve the issue, even asking for the user intervention with a popup or some other fix.

Not to mention the fact that, more importantly, this problem is not documented at all but instead the user is encouraged to simply copy and paste profiles which make this issue a bug from a user perspective.

I hope this thread is helpful to other users.

Key4.db and login.json are not OS-specific, so I could copy them to a flashdrive and from there, copy them to my profile map in Linux Mint 19.2. And it worked! Now, I have just booted up LM again, and guess what? All my logins and passwords are gone again! Key4.db and login.json have gone back to null content. I copied those files again, and it is working now. It seems FF does some sort of check at bootup, and does not recognise those files as authenthic. What other files or settings do I need to copy or change?

Hi Lex Noyb

Did you verify that Firefox is still using the same profile?

Was there a logins.json.corrupt file created?

Hi, cor-el, Thanks for the speedy response to my question. I am not all that familiar with LM's filing system yet, so I have no way to determine if it's still the same profile, or if logins.json has been corrupted. I have just rebooted LM, and now it seems to still be working with the 'new' file, so I have access to my logins again, but for how long? Would it help to create an account on some random website, so that logins.json gets updated under LM?

During the last week I have logged in to FF on LM19.2 a couple of times, and, so far, the issue hasn't come up again. I suppose it was a one-of issue. I now have access to my logins and pw's, so I think the problem is solved.