This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

restoring previous session on a new computter

  • 4 replies
  • 1 has this problem
  • 1 view
  • Last reply by FredMcD

more options

Hi, I had to erase all of my data in order to set up a fresh operating system on my computer. I made a firefox account and synced all my data before wiping my computer. I want to restore my previous sessions I was using before erasing all of my data, however can't figure out how. Thanks.

Hi, I had to erase all of my data in order to set up a fresh operating system on my computer. I made a firefox account and synced all my data before wiping my computer. I want to restore my previous sessions I was using before erasing all of my data, however can't figure out how. Thanks.

Chosen solution

FredMcD said

When you 'set up a fresh operating system,' do you mean you did a system refresh? If so, did you select to save your data? Using the computer's file browser, open your user folder. Look for a folder called Windows.old

I was running linux before and needed windows so I deleted all my old data and installed windows. I figured out how to open all my old tabs.. I clicked the 3 lines in firefox, clicked my username and scrolling down could see my old tabs underneath the signout option. I was able to click each one individually to open the old tabs. Thank you so much for your help!

Read this answer in context 👍 0

All Replies (4)

more options

When you 'set up a fresh operating system,' do you mean you did a system refresh? If so, did you select to save your data?

Using the computer's file browser, open your user folder. Look for a folder called Windows.old

more options

You need to place a sessionstore.jsonlz4 in the current profile folder to restore that last session.

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


You can copy certain files with Firefox closed to the current profile folder to transfer or recover personal data. Note that best is to avoid copying a full profile folder.


  • 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;32+) and key4.db (decryption key;58+) for Passwords saved in the Password Manager
    key3.db support ended in 73+; to use key3.db in 58-72, make sure to remove key4.db
  • cert9.db (58+) for (intermediate) 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)
more options

Chosen Solution

FredMcD said

When you 'set up a fresh operating system,' do you mean you did a system refresh? If so, did you select to save your data? Using the computer's file browser, open your user folder. Look for a folder called Windows.old

I was running linux before and needed windows so I deleted all my old data and installed windows. I figured out how to open all my old tabs.. I clicked the 3 lines in firefox, clicked my username and scrolling down could see my old tabs underneath the signout option. I was able to click each one individually to open the old tabs. Thank you so much for your help!

more options

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems. Go to that post and click the 'Solved' button to its right.