'https://support.mozilla.org/de/kb/firefox-fragt-immer-wieder-nach-master-passwort': Problem: this was no help
The above link tells me that, if I have the 'AVG Internet Security' software this problem would occur. But I do not have this software on my computer but rather the G-Data Internet Security. When I followed the steps as outlined on your Internet site, the result is the same afterwords. As soon as I restart Firefox, the message pops up again and again that I should enter my master password. This only occurs after I installed the latest Firefox (71.0, 32-bit).
Additional System Details
- Shockwave Flash 32.0 r0
- User Agent: Mozilla/5.0 (Windows NT 6.1; rv:71.0) Gecko/20100101 Firefox/71.0
A possible cause could be that your security software tries to add its certificate to Firefox. AVG did this in a way that required to enter the master password. That is the reasoning behind what you posted above.
If this happens each time you start Firefox and you do use Sync then this happens because Firefox stores the Sync credentials in the password manager and the MP is required to unlock the password store.
Other reasons can be having a login stored for you home page.