Hi, sorry to hear that. Maybe, probably not is where we are going. If there is a OldFirefoxProfile folder on your desktop, maybe. Please look here to see if it just made a new Profile and your older one is till there.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

So with luck there is 2 mixed up alphabet Folders here.

If on the Desktop or in the Profile folder then can : you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem. Never work with original files.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

For the future : As with everything related to a computer, back it up :

• 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

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

I found no "old firefox" or "old profiles" files on my hard drive. Your recommended Mozilla Support site told me to RUN %APPDATA%\Mozilla\Firefox\Profiles\, and I did. It produced C\Documents and Settings\Karen Gill-More\Application Data\Mozilla\Firefox\Profiles\4ix0gnk7.default. Using Import and Restore from the LIBRARY menu to run 4ix0gnk7.default Brought in only the recent bookmarks and none of the 10 years of data that have been lost. I have found that my Firefox version of 52.6.0 is an "esr" version (to be compatible with my now unsupported XP operating system software. My previous Firefox software load of 48 or lower, was NOT an "esr" version. Did installing the 52.6.0 lose my history and bookmarks?? Will installing a 48 or lower version of Firefox allow me to recover my lost history and/or bookmarks?? Would installing Windows 10 with the current version of Firefox recover my lost history and/or bookmarks?? Is there anyplace in the world on a Firefox server that my old profile data might be stored??

I found no "old firefox" or "old profiles" files on my hard drive. Your recommended Mozilla Support site told me to RUN %APPDATA%\Mozilla\Firefox\Profiles\, and I did. It produced C\Documents and Settings\Karen Gill-More\Application Data\Mozilla\Firefox\Profiles\4ix0gnk7.default. Using Import and Restore from the LIBRARY menu to run 4ix0gnk7.default Brought in only the recent bookmarks and none of the 10 years of data that have been lost. I have found that my Firefox version of 52.6.0 is an "esr" version (to be compatible with my now unsupported XP operating system software. My previous Firefox software load of 48 or lower, was NOT an "esr" version. Did installing the 52.6.0 lose my history and bookmarks?? Will installing a 48 or lower version of Firefox allow me to recover my lost history and/or bookmarks?? Would installing Windows 10 with the current version of Firefox recover my lost history and/or bookmarks?? Is there anyplace in the world on a Firefox server that my old profile data might be stored??

Hi, well seems like found some bookmarks. That is better than no bookmarks. Which unfortunately is the answer to your question which of course is not what you wanted to hear. There is never any data saved on Mozilla servers of your info unless you were Sync'ing 2 devices and had a account.

this would be the name of the folder OldFirefoxProfile on your Desktop if there was one.

No, installing nothing will get your Bookmarks back unless you had a backup :

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

You should have been switched to ESR in March 2017. The ESR would only be temporary as of June Mozilla is stopping support for XP.

• https://support.mozilla.org/en-US/kb/end-support-windows-xp-and-vista

As Volunteer Support Contributor I can empathize with your loss.

Aren't there any backups in the bookmarkbackups folder, either uncompressed .json or compressed jsonlz4 that can be used to restore bookmarks?

If a reset would have been used then the new profile folder would have gotten a time stamp appended.

Is the profile folder you found the only folder in that location?

• C\Documents and Settings\Karen Gill-More\Application Data\Mozilla\Firefox\Profiles\

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

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.

Thanks for your help! All the .json files only have bookmarks after March 2018. I don't have an account for syncing a 2nd device, so nothing on Firefox server. They are gone!! Thanks again

Thanks for your help! All the .json files only have bookmarks after March 2018. I don't have an account for syncing a 2nd device, so nothing on Firefox server. They are gone!! Thanks again