Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Urgent: Firefox crashed upon upgrade - Everything gone

  • 8 replies
  • 1 has this problem
  • 7 views
  • Last reply by cor-el

more options

I was prompted and downloaded the latest upgrade install file (72.0.2), closed Firefox and ran the upgrade. The resulting web page had a welcome tab and privacy tab as if this was the first time I'm using Firefox. All my tabs, bookmarks, settings, add-ins, authenticating credentials and history have disappeared. No Restore previous session was available. This is major loss that takes away all the tools and knowledge based I had accumulated over many years. It not only devastates my ability to function online but also kills the tasks I had been working on for a couple of weeks. I was able to find an excellent resource at https://support.mozilla.org/en-US/questions/1204253 which lead me to explore the Firefox files in sessionstore-backups folder. There is a file in there called previous.jsonlz4 which was saved about 15 minutes before the crash. I can see its contents using the tool at https://www.jeffersonscher.com/ffu/scrounger.html but don't know what to do next. There is no recovery.baklz4 file in this folder. Is there anything I can do to recover my browser as it was before the crash with my tabs, bookmarks, add-ons and my authentication credentials to various sites so I can be functional again?

I was prompted and downloaded the latest upgrade install file (72.0.2), closed Firefox and ran the upgrade. The resulting web page had a welcome tab and privacy tab as if this was the first time I'm using Firefox. All my tabs, bookmarks, settings, add-ins, authenticating credentials and history have disappeared. No Restore previous session was available. This is major loss that takes away all the tools and knowledge based I had accumulated over many years. It not only devastates my ability to function online but also kills the tasks I had been working on for a couple of weeks. I was able to find an excellent resource at https://support.mozilla.org/en-US/questions/1204253 which lead me to explore the Firefox files in sessionstore-backups folder. There is a file in there called previous.jsonlz4 which was saved about 15 minutes before the crash. I can see its contents using the tool at https://www.jeffersonscher.com/ffu/scrounger.html but don't know what to do next. There is no recovery.baklz4 file in this folder. Is there anything I can do to recover my browser as it was before the crash with my tabs, bookmarks, add-ons and my authentication credentials to various sites so I can be functional again?

Modified by Malik

Chosen solution

If you lost personal data then it is possible that a new default-release profile folder has been created. See "Determine if Firefox has created a new profile":

You can open the about:profiles page via the location bar to check whether multiple profiles are present and what profile Firefox currently is using.

See also:

Read this answer in context 👍 1

All Replies (8)

more options
more options
more options

Chosen Solution

If you lost personal data then it is possible that a new default-release profile folder has been created. See "Determine if Firefox has created a new profile":

You can open the about:profiles page via the location bar to check whether multiple profiles are present and what profile Firefox currently is using.

See also:

more options

Thank you all. What I see at about:profiles is attached. Not sure of the difference between the two. Is it safe to make the first profile as default?

Also attached are the contents of Old Firefox Data folder at Desktop. Most folders have timestamp of when it crashed. The files in sessionrestore-backups are date stamped from 6 months ago.

The Bookmarks, minidumps, and add-in sub-folders here are empty.

Modified by Malik

more options

Malik said

Not sure of the difference between the two.

You need to look at the time/date stamp of the folders. Picking the one from before the problem started might be best.

more options

I tried "Launch Profile in new browser" on the non-active profile and viola! It opened another window with all my content intact. I assume I can use the "Set as default Profile" button and my Firefox crash problems will be over. Right? How does one manually backup profile periodically just to be on the safe side? Thank goodness for the design that allows one to recover that wonderful browser. Firefox is not an operating system like Chrome but it sure is a work platform.

Modified by Malik

more options

Pick a folder you want to restore from. Open another file explorer window to the Current profile.

Copy the files you want, or all of them, from the old to the current with Firefox closed. Overwrite if asked.

more options