Try a System Restore, to a point in time prior to updating to Firefox 58, and then export the bookmarks to HTML, re-update Firefox, and import those HTML bookmarks back in to Firefox.

Note that using System Restore can cause your Firefox installation to get corrupted because only white-listed files are restored.

• always be cautious with using System Restore and make sure to backup your profile folder
• you may lose data in the Firefox profile folder like .js and .ini files
• you may need to reinstall affected software

Do you have JSON backups in the bookmarkbackups folder?

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

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 can check if you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created.

• https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems
• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Mkll said

Try a System Restore, to a point in time prior to updating to Firefox 58, and then export the bookmarks to HTML, re-update Firefox, and import those HTML bookmarks back in to Firefox.

Thanks Mkii for reply. System Restore in Windows 10 is another challenge. Always been ok in Vista but never quite got the hang of it in 10. That is for another day. Managed to recover Bookmarks from JSON file re Oct 2017 .

cor-el said

Note that using System Restore can cause your Firefox installation to get corrupted because only white-listed files are restored.

• always be cautious with using System Restore and make sure to backup your profile folder
• you may lose data in the Firefox profile folder like .js and .ini files
• you may need to reinstall affected software

---

Do you have JSON backups in the bookmarkbackups folder?

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

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 can check if you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created.

• https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems
• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Thanks cor-el, managed to recover Bookmarks as at October 2017 date thro JSON file. Although being honest it was more by luck than judgment..... thanks again

You're welcome and glad to read you managed to recover your bookmarks.