Hi mikewhitmore, could you clarify this for me. In Firefox, the page that appears when you click the Home button is usually called the home page. Then there is a toolbar area above the page.

By "user history" do you mean "browsing history," pages you browsed before? (That's what I'm assuming for the rest of this reply.)

Where did the button disappear from?

If it was from the toolbar area:

Firefox has a "Library" button (looks like a few books) that provides access to history, bookmarks, and downloads, and it also has a "History" button (looks like a clock) specifically for history. If one of those is gone, you could look in the Customize page and see whether it is available to drag-and-drop back onto the toolbar. This article has more info on that: Customize Firefox controls, buttons and toolbars. If the icon is completely lost and can't be found anywhere, you can use the "Restore Defaults" button at the bottom of the Customize page to go back to the starting toolbar layout and re-customize from there.

If you are missing an add-on button, then maybe that add-on is disabled or missing??

If it was from the page:

What page is your home page? For example, the built-in page showing Top Sites, etc., or a site out on the web?

Oh, random thought: is the problem that your accounts list on Fastmail was cleared? The one described in this article: https://www.fastmail.com/help/account/showlogin.html

A user reported last month that the list kept getting cleared in Firefox 66 on his Mac. Most likely, it was due to a problem retaining cookies, but I don't think we got confirmation that it was solved.