Hi Mark

Have you saved passwords for sites you have account for in Firefox? The primary password is there to protect the rest of the passwords you have saved. If you haven't saved passwords or you are the only user of your device and it has a good enough system user login user password, then you can disable the primary password by going to: Edit > Settings > Privacy and Security > Passwords > Untick: "Use Primary Password".

Are you using Sync as this is a possible reason to ask for the Primary Password when you start Firefox ?

Using Sync is a possible reason to ask for the Primary Password at startup. This is because the credentials to login to the Sync account are stored in the Password Manager and you need to enter the Primary Password to unlock the passwords and connect/login to the Sync account.

• https://support.mozilla.org/en-US/kb/using-primary-password-sync