Firefox uses two locations in the hidden "AppData" location for the Firefox profile folder. One location in "AppDataRoaming" for personal data like bookmarks and logins and another location in "AppDataLocal" for temporary files like the disk cache.

Primary location used for the main profile that keeps your personal data (Root Directory on about:profiles).

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>

See also:

• https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them

You can copy certain files with Firefox closed from another profile or backup to the current profile folder to transfer personal data. Note that best is to avoid restoring a full profile folder and only restore important files that are safe to restore/transfer.

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page 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
• 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 (encrypted logins) and key4.db (encryption key/primary password) for logins saved in the Password Manager
• cert9.db for certificates stored in the Certificate Manager
• persdict.dat for words added to the spell 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)

Thanks for the help. I found the places.sqlite file on the old disc and replaced the new one with the old one. I now see all my old bookmarks.

However, when I click on any of the toolbar bookmarks, Firefox brings up the Firefox login page or it's Add-Ons page. Some of the bookmarks bring up completely different web pages unrelated to the bookmark.

Very strange. Did I do something wrong, or not complete this change?

Oh, and Firefox will no longer bookmark anything.

If you use Sync, best is to disconnect Sync temporarily during troubleshooting.

This could be a problem with the places.sqlite and favicons.sqlite files in the Firefox profile folder.

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

If errors are reported with "Verify Integrity", close and restart Firefox or reboot 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 bookmarks 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 on the "Help -> More Troubleshooting Information" (about:support) page 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

Note that you may have to create a new profile and start from scratch in case some files you copied are corrupted due to the crash.

I removed all toolbar bookmarks. All the other older bookmarks are now going to the correct web pages. I still have the problem that Firefox will not bookmark any web page anywhere other than on the toolbar.

Removed both places.sqlite and favicons.sqlite files and restarted Firefox. No change. Still cannot bookmark anything other than on the toolbar.

I know I've missed something, but can't figure out what it is.