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

• use the "Places Database" -> "Verify Integrity" button in "Help -> More Troubleshooting Information" (about:support)

If errors are reported with "Verify Integrity", close and restart Firefox or reboot the computer and retry.

If "Verify Integrity" cannot repair places.sqlite, rename/remove all places.sqlite and favicons.sqlite files in the Firefox profile folder with Firefox closed. Firefox will rebuild places.sqlite and restore the bookmarks from the most 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
• you lose the history when a new places.sqlite is created

You may have to restore an older backup in the bookmarkbackups folder via the Bookmarks Manager (Library).

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

See also:

• https://support.mozilla.org/en-US/kb/fix-bookmarks-and-history-will-not-be-functional
• https://support.mozilla.org/en-US/kb/cant-add-change-or-save-bookmarks

You can use the button in "Help -> More Troubleshooting Information" (about:support) to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More 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

I did something wrong and now everything is gone book marks, passwords, history, tabs all empty. I wanted to use this backup copy bookmarks-2026-03-23_750_nNAHeljyFcijdjaRFADv1v4DJlbCKzqVJsZP5KAydEU=.jsonlz4" but It never gave me a chance. I am not real experienced at this. I think I created a whole new profile. Step by step what do I do next?

You may have switched to a new profile (or used the Firefox refresh feature);

• https://support.mozilla.org/en-US/kb/recover-user-data-missing-after-firefox-update

You can look at this tool to inspect a compressed jsonlz4 bookmarks backup and possibly convert this file to HTML to be able to import/merge bookmarks. This tool works locally, no uploading is done.

• https://www.jeffersonscher.com/res/bookbackreader.html

I have got the bookmarks back to something usable. Now how do I get my passwords back?