Do you use Firefox's Password Manager? Normally you would only need a Master Password if you use Firefox's Password Manager and Firefox needs to fill a saved login.

See the "Removing the master password" section of the following article:

Use a Primary Password to protect stored logins and passwords

Does that work?

Firefox will not accept the password. I'm pretty sure I recorded it correctly.

Bobbily said

Firefox will not accept the password. I'm pretty sure I recorded it correctly.

Sounds like the password created doesn't match the inputted password. You need to be sure on this.

OK, thanks for responding. I will use a different browser.

There is a method to remove an unwanted Master Password, but it will clear any logins saved in Firefox's password manager. See: Reset your Primary Password if you've forgotten it.

Try the Firefox version from the official Mozilla server if you currently use a version from the repositories of your Linux distribution.

The MP is only required once to login to the Firefox Password Manager. Once you are logged in and you can see the usernames in the Password Manager then you shouldn't get additional master password prompts.

You wrote "Entered the password several times". Is this about the master password or about entering the password on a web page in a password field?

If Firefox doesn't accept the MP then then you can rename the logins.json and key4.db files in the profile folder. You may have to remove pkcs11.txt and secmode.db as well if the issue persists.

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:preferences page.

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

Thanks to the community for the attention. I am apparently too stupid to make use of it. Senility is a disabling disease, but so far it's been better than nothing.