[v57+] Places Maintenance is built into Firefox.

Type about:support<enter> in the address bar.

You will find Places Database near the bottom. Press the Verify Integrity button.

When done, copy and post the results here.

> Task: checkIntegrity - Unable to check favicons.sqlite integrity: [Exception... "Could not open connection to C:\Users\Emma\AppData\Roaming\Mozilla\Firefox\Profiles\m08citmw.default\favicons.sqlite: 2153971713" nsresult: "0x80630001 (NS_ERROR_STORAGE_BUSY)" location: "JS frame :: resource://gre/modules/Sqlite.jsm :: openConnection/</< :: line 985" data: no] > Task: invalidateCaches - The task queue was cleared by an error in another task. > Task: checkCoherence - The task queue was cleared by an error in another task. > 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

Looks like something is blocking access to the file. places.sqlite : History and Bookmarks

The only thing I know of is to delete this file. Once you have done so, a new file will be created using a bookmarks backup file. But history has no backup.

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the above file. Then rename or delete it. Restart Firefox.

Back up and restore information in Firefox profiles.{web link} I use an add-on that makes backups of my user profile, Just In Case. Unfortunately, it is not compatible with the current Firefox.

Every now and then, open the profile folder and create a copy of the current profile as is to another location on your hard drive. This way you will have a backup.

If you do this each day, you will not lose much data. This should be done with Firefox Closed.

Note: In case you need to restore from these backups, you may need to overwrite old or corrupted files.

Thanks very much for your assistance. Everything seems to have come back to normal. I moved the profile file to the desktop and restarted Firefox and it promptly created a new profile folder. But I no longer had access to my bookmarks. So I deleted this new profile folder and brought back the old one. For some reason, everything is working fine now. Thanks again.

That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

And remember to make backups of your profile.

Thanks very much. I'll remember the backups.