Hi, you do not mention another device that you Sync with. This there fore is the problem. It appears from your question, that you are using Firefox Sync as a back up service. This is not what Sync is designed to do. The Firefox Sync service takes a copy of the data you wish to include and transfers it to a second device (typically a mobile device such as a tablet or a telephone) running a copy of Firefox. The storage in between all attached devices is both temporary and fragile and is not stable enough to be (and is not designed as) a reliable backup service.

If you have a copy of your Firefox profile for desktop Firefox, you may be able to recover your bookmarks and other data. Please have a read of these articles.

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

If you have a copy of your data on a mobile version of Firefox, please follow these instructions to connect it to Firefox Sync to copy your data.

• https://support.mozilla.org/en-US/kb/how-do-i-set-sync-my-computer#w_connect-additional-devices-to-sync_

Please let us know if this solved your issue or if need further assistance.

I may have pointed this out in your last question regarding your Video Card Drivers : u'unavailable = bad

featureLog: {u'fallbacks': [], u'features': [{u'status': u'blocked', u'log': [{u'status': u'blocked', u'message': u'Acceleration blocked by platform', u'type': u'default'}], u'description': u'Compositing', u'name': u'HW_COMPOSITING'}, {u'status': u'unavailable', u'log': [{u'status': u'unavailable', u'message': u'Hardware compositing is disabled', u'type': u'default'}], u'description': u'OpenGL Compositing', u'name': u'OPENGL_COMPOSITING'}, {u'status': u'unavailable', u'log':

Firefox 24 used a completely different version of Sync (version 1.1) than Firefox 29 and later versions now use - version 1.5. Sync 1.1 used a completely different server cluster than Sync 1.5 uses; both co-existed for a little over a year to support the older Firefox 28 version, but those old 1.1 servers don't even exist any longer. Firefox 24 with Sync 1.1 just won't connect to the Sync 1.5 version server - totally different log in scheme with no backwards compatibility for connecting.

Plus there have been a number of major changes made to Sync between Firefox 42 and 59, so there might be a compatibility issue between those two versions with certain files.

1. One copy of the users Sync data is retained on the Sync server; there are no backups. If you data is gone, there is nothing to "recover".
2. Firefox does store multiple bookmarksbackup files in the Profile folder; iirc, Firefox 24 saved 10 backup files. (Later versions keep 15 bookmark backup files.) See if this helps your recover your bookmarks. https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them As far as other data goes, you can view the files in the Profile folder and check the dates on those files to see if a backup was created - sometimes an .old file is created. https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

Thank you, guys! The post about restoring from bookmarksbackup did help. Now everything is back. Also, it's a good thing you pointed out that Sync is not a backup service - I'll remember that (got confused by similar option on my smartphone where sync is actually a backup on the cloud).

For those who manages several versions like I do:

I found out from the linked pages that firefox actually has a local storage for bookmarks called places.sqlite. So now I simply do my own backup of that file before switching to older versions. Then I just rename it back when I select the newest firefox again. Not sure it's a proper way of handling it, but it works for me.

Hope it helps.