I am using Firefox since several years with a PrimaryPassword for saved passwords. With Windows 10 it is used since a year or so. I regularily kept Firefox open for several days, but had no issue with it. But since some weeks firefox is asking for the Primary Password every day. This is quite anoying. After entering the password again, it continues to work, but will ask for the password on the next day again. Another post talks about a possible issue with some specific virus scanners, but I am just using Microsoft Defender Antivirus, which ships with Windows 10. I did not add any Add-on recently, so I suppose an issue with one of the latest Firefox updates (current version is 90.0.2 64-bit on Windows 10). Thanks for any tips.