Sorry to hear about this negative update experience. Usually it goes very smoothly. Did you lose any other data, or only saved logins?

I lost everything, all my data is gone. Turned off my laptop yesterday and everything was fine, switched it on this morning and everything was gone, no warning, no "please create an account", just "we have updated firefox and deleted all your data". Is there any way of retrieving my info?

You should never get a dialog from Firefox saying it has deleted all your data. Sometimes Firefox will create a new profile, so I suggest checking that in a moment.

First though, If you haven't already, could you close out of Firefox and do a normal Windows shutdown and restart to complete any pending updates and release any file locks.

If Firefox again starts up without your data, could you check whether your stuff is available in a different profile, as follows:

Profile Manager Page

Inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!)

The profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

Do you have another profile named default or default-release or default-longnumber listed on this page? If so, you can check whether it is the one you were using recently by clicking its Launch profile in new browser button.

If it isn't what you want, simply close that new window.

If it IS what you want, back on the about:profiles page, click the Set as default profile button for that profile so Firefox uses it automatically at the next startup.

Anything?

Hi, That info would be very helpful if I had a profile before firefox updated. I didn't, everything was saved locally (Firefox has never given any indication that it would delete my information without warning). It looks like the a new folder "old firefox data" was created but there is no instructions on how to use this info, can it be used to restore my data? Whilst I don't normally mind that firefox updates automatically to do so whilst deleting all my information is very annoying, it is likely going to take me weeks to discover all the lost data and reset all my passwords.

That info would be very helpful if I had a profile before firefox updated. I didn't, everything was saved locally

Profile folders are local folders.

It looks like the a new folder "old firefox data" was created but there is no instructions on how to use this info, can it be used to restore my data?

The Old Firefox Data folder is created when Firefox performs a Refresh. If you check inside the folder, does it look like freshly updated data? If you double-click down into the profile folder, and then into the bookmarkbackups folder, the creation dates are indicated in the file names, so that's a pretty good indicator of freshness. If that data looks useful, we can describe some ways to utilize it.