Typically, toolbars are installed as addons. You can open the addon manager by entering about:addons in your Firefox address bar.

In terms of why they are disappearing, it could be because they are out-dated. To update your addons, please try selecting Check for updates from the gear icon on the addons manager.

Note: You may need to restart Firefox for addon updates to complete.

Let us know if this fixes your toolbars.

Specifically, which toolbars did you add? And the name of the extensions that install those toolbars?

Overall, there have been a number of support threads started in the past month or so about "disappearing" UI elements in Firefox 44. I don't recall if it was toolbars and toolbar buttons, or just toolbar buttons that were added by an extension. I don't recall specific extension names involved, but my impression was that "something" that was added to Firefox 44 was buggy and was causing the issue.

One thing that seemed common was that when Firefox was opened the UI element was missing, but when the user opened a 2nd window it would appear. iirc, that was reproducible at will by the user and sometimes that problem "fixed itself" for the rest of that session.

Wesley Branton said

Typically, toolbars are installed as addons. You can open the addon manager by entering about:addons in your Firefox address bar. In terms of why they are disappearing, it could be because they are out-dated. To update your addons, please try selecting Check for updates from the gear icon on the addons manager. Note: You may need to restart Firefox for addon updates to complete. Let us know if this fixes your toolbars.

Thank you very much!!

Wesley Branton said

Typically, toolbars are installed as addons. You can open the addon manager by entering about:addons in your Firefox address bar. In terms of why they are disappearing, it could be because they are out-dated. To update your addons, please try selecting Check for updates from the gear icon on the addons manager. Note: You may need to restart Firefox for addon updates to complete. Let us know if this fixes your toolbars.

Thank you so much!

I have the same issue and as much as I try to download NECTAR Toolbar, Firefox does not allow me to enable it. WHY?

Chantal Rondepierre-Bristow said

I have the same issue and as much as I try to download NECTAR Toolbar, Firefox does not allow me to enable it. WHY?

Doing the steps in the solution to this thread will probably fix the issue. Try them and let us know if the issue is resolved.

I tried the following and it worked (after I posted in the forum)

In the Location bar, type about:config and press Enter.

   The about:config "This might void your warranty!" warning page may appear. Click I'll be careful, I promise! to continue to the about:config page.