Hi ChayaCooper, were the bookmarks deleted completely? To cross check that, you can use either:

• Bookmarks Sidebar (Ctrl+b) -- one of the top level categories should be Bookmarks Toolbar
• Library window (Ctrl+Shift+b) -- click Bookmarks Toolbar in the left panel
• Bookmarks menu (Alt+b) -- click the Bookmarks Toolbar fly-out a few items down the menu

If the problem is only with the display of the bar, what is the current status?

(A) Bar appears and is empty

Try the Restore Defaults button at the bottom of the Customize screen -- Customize Firefox controls, buttons and toolbars

(B) Bar does not appear

Could you double-check that it is currently set to display? I'm sure you've done this, but just for completeness:

To turn different bars on and off, you can use one of these methods to show the toolbar list and select the desired bars there:

• right-click (on Mac Ctrl+click) a blank spot on the tab bar (or the "+" button)
• (menu bar) View > Toolbars
  On Windows, tap the Alt key to activate the menu bar temporarily.
• in Customize mode > Toolbars button (see: Customize Firefox controls, buttons and toolbars)

To turn on the Bookmarks Toolbar, Menu Bar, or other bars, click it on the list.

(C) Bar displays for a moment at startup and then vanishes

This seems to be related to the automatic session restore features and strikes some users randomly. More advice if it seems relevant. Or check out: https://support.mozilla.org/questions/1255289

Note that the bookmarks shouldn't be affected by a Firefox update. If this happens then possible causes are security software that is interfering somehow with the places.sqlite database (bookmarks and history).

You can check for problems with the places.sqlite and favicons.sqlite files in the Firefox profile folder.

• use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page

In case errors are reported with "Verify Integrity" close and restart Firefox and retry.

You can check if there are backups in the bookmarkbackups folder available.

• Bookmarks -> Show All Bookmarks -> Import & Backup -> Restore
• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

The name of an automatically created JSON bookmarks backup in the bookmarkbackups folder includes a total item count (folders and separators included) and an hash value to prevent saving the same backup more than once. You also see this count in the Restore menu drop-down list.

• bookmarks-YYYY-MM-DD_<item count>_<hash>.jsonlz4.

Verify Integrity: I've restarted Firefox countless times since this occurred. Is there anything else that I can do to troubleshoot the error message "The task queue was cleared by an error in another task" for these Tasks: expire, originFrecencyStats, vacuum, stats, _refreshUI?

Restore Backup: Unfortunately, as I mentioned in my post, restoring a backup didn't help.

Hi ChayaCooper, can you share more of the Verify Integrity report?

If "Verify Integrity" cannot repair places.sqlite then remove all places.sqlite and favicons.sqlite files in the Firefox profile folder. Firefox will rebuild places.sqlite and restore the bookmarks from a recent JSON backup in the bookmarkbackups folder.

• keep a backup copy of places.sqlite in case a new places.sqlite database has to be created

See also:

• https://support.mozilla.org/en-US/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file
• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

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

jscher2000 said

Hi ChayaCooper, can you share more of the Verify Integrity report?

Verify Integrity

> Task: checkIntegrity + The places.sqlite database is sane + The favicons.sqlite database is sane > Task: invalidateCaches + The caches have been invalidated > Task: checkCoherence + The database is coherent > Task: expire - The task queue was cleared by an error in another task. > Task: originFrecencyStats - The task queue was cleared by an error in another task. > Task: vacuum - The task queue was cleared by an error in another task. > Task: stats - The task queue was cleared by an error in another task. > Task: _refreshUI - The task queue was cleared by an error in another task.