Firefox Sync stores its credentials data to login to Sync in the Password Manager, so if you use a master password then you need to enter the MP every time you start Firefox to be able to connect to Sync.

I understand that. After further research it appears I do not need sync. How do I turn it off?

Just to be sure: A possible cause of the master password prompt at startup can be the hotfix extension to add the new intermediate certificate to the Firefox Certificate Manager. If you have this extension listed on the about:studies page then try to remove it when possible.

If you run Firefox 66.0.5 or later then you no longer need an extension or other workarounds to install the new certificate. You can also check the about:addons page for a (hot)fix extension and remove this extension when present.

• https://support.mozilla.org/en-US/kb/update-firefox-latest-version

You can toggle this pref to false on the about:config page to disable Sync in Firefox 60+.

• identity.fxaccounts.enabled = false

You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.

• http://kb.mozillazine.org/about:config

FF version 67.0.4. No studies installed. Hotfix not found. So changing item to false appears to be my only option left.

Note the you also get a MP prompt if you open a web page on startup where you have saved a password. Some extensions may also prompt for the MP.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

First some background. Usually update when prompted. When option to create userid occurred I created one and verified it. Not sure what it would be used for. As mentioned earlier I only have one machine running FF therefore SYNC is not necessary.

Only extension showing is something called TinyEye. Running default theme. It is the only one listed.

Prior to creating userid I would be prompted for MP the first time it was needed. Never asked during startup.

What do I "get" by having a userid? Conversely what would I "lose" if I deleted the userid? The prompt at startup is more of nuisance not really a problem.

You can use a Firefox Account for more services like Firefox Monitor and Firefox Send and Firefox Lockwise.

• https://support.mozilla.org/en-US/kb/access-mozilla-services-firefox-account