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.

When done, copy and post the results here.

https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional

How did you transfer this data ?

Did you use Sync or did you copy files ?

If you used the latter, did you copy a full profile folder or merely specific files ?

Hi FredMcD, Thank you very much for your reply. I don't have sync. I got the below when I pressed the Verify Integrity button. Any advice on what I need to do is highly appreciate. Thanks!

> Task: checkIntegrity - Unable to fix corruption, places.sqlite will be replaced on next startup > 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 - The task queue was cleared by an error in another task. > Task: _refreshUI - The task queue was cleared by an error in another task.

Hi cor-el, Thank you very much for your reply. I created a back-up disk (Time Machine) and transferred all the data to new Mac OS using this disk. I did not pick and choose anything and so I am assuming I transferred all the files. Thanks!

Your places.sqlite database is corrupted.

If "Verify Integrity" cannot repair places.sqlite, rename/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:profiles page.

• Help -> Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Hi cor-el,

Thank you so much! I found a couple of places.sqlite files. I found a couple of folders named "old firefox data" and found the places.sqlite files there, but also within the (current) "Firefox" folder, in the "Profiles" folder, I seem to have 2 folders which both have "places.sqlite" in them.

When I opened one of the folders, I found that most of the files are date 2018 all but one 2 files (prefs.js and prefs.js.bak).

Should (Can) I delete this old folder altogether from the Profiles folder (or will it cause problems)?

I am guessing the places.sqlite file that I really need to delete is the one inside the newer folder that is in the "Profiles" folder.

Is my understanding correct? Thank you.

If you restored a rather old profile then it might be better to start with a fresh profile and copy as less files as possible from the backup.
This places.sqlite file is either corrupt or not compatible, so you will have to remove it and possibly restore a backup from the bookmarkbackups folder.

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

You can copy specific files with Firefox closed to the current profile folder to recover personal data.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

• bookmarks and history: places.sqlite
• favicons: favicons.sqlite
• bookmark backups: compressed .jsonlz4 JSON backups in the bookmarkbackups folder
• cookies.sqlite for the Cookies
• formhistory.sqlite for saved autocomplete Form Data
• logins.json (passwords) and key4.db (58+) or key3.db (57 and older) (decryption key) for Passwords saved in the Password Manager
  if you only have key3.db then make sure to remove an existing key4.db
• cert9.db (58+) or cert8.db (57 and older) for (intermediate) certificates stored in the Certificate Manager
  if you only have cert8.db then make sure to remove an existing cert9.db
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other website specific data (Site Preferences)
• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

Hi cor-el, Thank you so much! I created a new profile and all is going well now. Thank you so much for your great help!

Thank you to FredMcD, too!

Glad to help. Safe Surfing.

Thank you!!