If you have sync, and there is a problem anywhere, Shut Down Sync Immediately On All Devices to prevent the problem from spreading. Once the problem is fixed, perform the same repair on all computers/profiles before using sync again.

[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.

If any errors are reported, check this link: https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

The places.sqlite file contains your History and Bookmarks. And it looks like it is corrupted.

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. The browser should then create a new place.sqlite and recover your bookmarks from the backup files.

Note: Your history is not backed up and will be lost.

Hi Fred. I appreciate your help. I did as you suggested, and as I was deleting duplicate bookmarks and reorganizing them, the problem started again. Should I have also renamed or deleted places.sqlite-shm and places.sqlite-wal in addition to places.sqlite?

Thank you. Bob

places.sqlite-shm (Shared Memory) and places.sqlite-wal (Write-Ahead Logging) are SQLite temp files and will only be present if Firefox is running and not when Firefox is closed.

Are you using Sync to sync bookmarks ?

If you rename/remove places.sqlite then this should remove all duplicates. If the backup Firefox automatically restored is already affected then restore an older backup.

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.

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

You also see this count in the Restore menu drop-down list.

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

Hi cor-el:

I tried the remedy you suggested, and it worked for a little while, then the duplicates started to appear again. I used the oldest backup that was available, which is clearly not old enough. This is most frustrating.

Bob