That sounds like Firefox's "full screen" view. Could you try

Command + Shift + f

to switch back to regular? The View menu might also work if you can access it when the top rolls down.

Note that the System Details list shows you run an older Firefox 64 version that is no longer supported with security updates.

Please update to the current Firefox 66.0.3 release.

• Firefox -> About Firefox
• https://support.mozilla.org/en-US/kb/update-firefox-latest-version
• https://www.mozilla.org/en-US/firefox/all/

jscher2000,

No, Firefox isn't in "full screen" view

cor-el,

I've tried several times, but Firefox 66.0.3 won't load...VERY exasperating!

Try to rename/remove xulstore.json and if present delete localstore.rdf in the Firefox profile folder with Firefox closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:preferences page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

cor-el,

When I removed "xulstore.json" with Firefox closed, not only did that not restore the toolbar, but also when I try to make the toolbar appear by moving the mouse pointer to the top of the screen the only wording on the left hand side that appears is the "apple" icon and "Firefox"...so I've also lost the "edit", "view", etc. functions. I then put "xulstore.json" back in the profile folder to see if that action would at least restore the functions I'd lost, but it did not (note: "localstore.rdf" is not present in the profile folder).

As a check to see if the toolbar is missing in another browser I went to Safari and found that it is missing there also. So the absent toolbar issue may be caused by a problem not attributable to a specific browser (?).

The main menu bar is controlled by the Mac OS and not by Firefo. I assume that Firefox passes this data to the MacOS and MacOS draws the toolbar.

You can try to uninstall Firefox (i.e. drag the Firefox icon from the Dock to the Trash) and reinstall Firefox.

• https://www.mozilla.org/en-US/firefox/all/

You can create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

jscher2000, cor-el,

Your mention, cor-el, of MacOS as the controller of the main menu bar [a.k.a. "toolbar" (?)] prompted me to search Google for iMac-specific info. I put in "browser toolbar missing on iMac" and found "How do I get my menu bar back on my Mac?". It suggested going to the main Apple menu in the browser toolbar, then to "system preferences-general-appearance-automatically hide and show the menu bar". I found that the latter link was checked (?...I don't remember doing that), so I removed the check and the browser toolbar was restored...made my day! That link, however, should NOT say "...hide and show...". The setting can only be one or the other, not both. Maybe I'll suggest that to Apple.

Thank you both for responding to my problem....