I have routinely sent in crash reports when this happens -- sometimes many times in the same day. I always keep a browser in reserve just in case, and lately have set Chrome up for more than temp use. (Just in case...) I figured eventually you code folks would figure it out and it does seem to have gotten better. Well, at least less frequent. And it's very good at retrieving my tabs, which is nice. I have used FF for a long time and really really like it. But the crashing and freezing is not good, because I do a lot of intense online research and it tends to kind of break the concentration, you know? Besides, now I have a worse problem to deal with. When I get that worked out as much as it's going to get worked out, I hope you've got Firefox worked out too. Cause I really do like it. (BTW, I have never had anything ride in on FF, but after reading the above I'll keep an eye on Chrome.)

Adding a cross link to your current question ~J99

• One computer: Win10 "update" trashed me. Lost all my browser data. All i got from FFwas link to pockets (ew)

Extra detail: FF48 freezes ["(Not Responding)"] within 5 minutes without fail, sometimes within mere seconds of opening. This happened maybe once every other day wtih FF47(or w/e # the previous version was) just once about every other day for me if that helps anything. I had to make sure to save all bookmarks before it randomly froze losing me all the bookmarks even with Session Manager extension installed and set to save the session every 15 minutes.

Another extra detail: The crash report listing does not show these as crashes so there's nothing my version of FF would be able to send in to have looked at. It just freezes and I have to taskmanager kill it or it will hang forever. After one of the complete uninstall/reinstalls where I had to sign-in again for FirefoxSync, the browser would freeze for a minute or two and then unfreeze so I thought I was getting somewhere. Then after about 5-6 of those iterations it went full-freeze on me again.

Is there something I can do to erase remnants of FF48 that Windows10 Uninstall/Remove Program doesn't remove to ensure I get a ...even more complete fresh reinstall?

There are some advanced methods that may help but lets try a couple of easier ones first of all.

1. With Windows in its own safe mode If you start Firefox in safemode, all plugins disabled, using a new additional profile and NOT connected to the internet what happens ? does that still freeze.
2. What happens if you use Firefox portable ESR that is a third party build of Firefox. if you download and install that as an additional browser does that work for you ?
   1. http://portableapps.com/apps/internet/firefox-portable-esr
   2. If that works ok then try the portable Fx48 does that also work ok ?

• if you have any crash reports pleas let us have the Crash IDs for the latest few. That's the text beginning bp-

Please advise if you are unsure how to do any of this I can provide help links if necessary,

Additionally please confirm you have done a clean install including deleting all the Firefox program files (NOT the profile files)

@John99: Thanks so much for responding and laying out some initial steps to remediate this issue. Here's how things went:

1. I reinstalled FF48(64-bit) but didn't load any extensions or my firefoxsync profile. In Safe Mode without internet it seemed to work but no pages were opened, video played, etc.

2. Firefox portable ESR was installed and worked fine for a short time (several pages loaded and several Youtube videos worked). I then added my FirefoxSync profile and Restarted it for my Extensions to load and upon the restart it froze outright but without the "(Not Responding)" notice which was the common feature of all previous freezes. I needed to kill it in Task Manager since it wouldn't close. It also caused the rare effect that my mouse wasn't able to go below the top of the Windows pin-bar along the bottom. I had to reopen Task Manager a couple of times because even it wouldn't respond to clicks via mouse if I didn't highlight Firefox there and kill it asap.

I'm going to hold off on loading my Sync profile in FF48 until your next response. Thanks again!

Important. Please do not remove, delete or rename any Firefox profiles you have. Do you have one on the Desktop created by Firefox Refresh  ? called old data or something similar.

Thanks for trying that. I know Firefox is not much good as a browser if it is not connected to the internet but check it out opening some saved web page on your computer just to see if it works. Then try it on the internet, but please do all this in safemode and without using Sync.

First indications are pointing the finger of suspicion at Sync &/or your profile.

I note you now mention that it is 64 bit Fx. I suggest you also download and install 32bit Fx that is what most people use & it should install as a separate browser. I don't if it has a separate profile from the 64 bit Firefox. I have only installed it after 32bit Firefox and have deliberately created its profile.

By all means try loading your profile information from Sync BUT

• Do that in a new profile
• Immediately back up that profile. However from what you say that may end up with a broken profile that freezes Firefox.
  • See Back up and restore information in Firefox profiles
  • Note Sync is not designed or intended to be a backup service. Your only reliable backups are those on your devices.
  • If you are not using Sync between two or more devices consider setting up a separate Operating System account and Syncing the Firefox on that. It is an easy method of ensuring you have something to sync with. Firefox sync will Sync as if that is a second device.

If you can get a working and up to date Firefox, possibly the 32bit new install then it should be possible to transfer stuff from the old profile or some backup you may have.

• See Recovering important data from an old profile

Have you got backups or good profiles on any of your devices ? Note a method of searching for profiles is looking for all the instances of places.sqlite

Up to Windows 10 I think Windows used to keep restorable copies of Profiles, using its previous Files!Folders system, but that probably does not happen now. What sort of important personal info will be in your profiles ? & have you backed it up besides using Sync ? How many devices and what are they that you use Sync on ? e.g smartphones or other desktop computers ? Although addons may be important, they are not personal thy are easily downloaded again. Bookmarks & passwords are personal and you may or may not consider them important, and may or may not have backed them up deliberately;or synced then successfully to another device. What's the current position with these ?

• Note Firefox does a pretty good job these days of making additional backups of Bookmarks See also
  • Restore bookmarks from backup or move them to another computer
  • Recover lost or missing Bookmarks

Thanks again for following up! This is quite a lot to get through so it might be a couple days before I have time to work on it all.

I will mention that it was the 32bit version that went bad. It was only after I had tried a Refresh that I realized it was 32bit and then tried the 64bit version (I installed the 64bit version a while ago, maybe last year, and I'm not exactly sure when it went back to 32bit...strange...)

And yes, I still have the folder named "Old Firefox Data" that was created on my desktop after the Refresh.

....aaaand both 32bit and 64bit versions have the same freezing/hanging issue.

Do they work ok when using a new Profile  ? in safe mode and with all plugins disabled ?

Is it only after you try to Sync that they freeze for instance ? (I can not remember how to reset portable ESR)