Hi ....

Let's discuss the missing session history files. Your screenshot doesn't show the usual things one would expect to find in that folder, such as the snapshots captured when Firefox updates. This could indicate that there is another profile folder with your old data in it.

If you haven't already, you may want to do a normal system shutdown and startup to release any file locks and complete any pending updates.

If your Firefox data does not magically reappear, the most likely scenarios for complete data loss are:

(1) A Refresh started but the migration of data from your old profile to your new profile was incomplete, or (2) Your old profile was locked, so Firefox ignored it and created a new one.

It's a lot of things to check, but if you go step by step, it's not too bad.

Did Firefox perform a Refresh?

Unless it was interrupted in progress, you should find a folder on your desktop named Old Firefox Data. Inside would be a semi-randomly-named folder with freshly updated files. Do you see anything like that?

If so, we'll suggest how to rescue key files or completely restore the earlier profile folder.

If not...

Does the Profile Manager list your immediately previous profile folder?

To check on that, inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list all the profiles Firefox is currently aware of. If you see a profile that is not currently set as default that looks promising, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but I think those are still "under construction" so please ignore them.)

Firefox should exit and then start up using the other profile. Is that the right one?

If it's not there...

Did Firefox orphan your old profile folder? Here's how to check whether there are additional profile folders in the standard location in addition to the one you're using. Start by opening your current Firefox profile folder using either:

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Open Folder" button, to launch a new window listing various files and folders in Windows Explorer.

In the Windows Explorer address bar, click the capitalized word Profiles to move up one level in the folder hierarchy. More than one folder here by any chance? Do the files in those folders look like they were last updated around the time of the update?

If you've got any promising looking folders, we can discuss next steps to recover use of them, and any session history files they contain.

Windows may have backed up your profile folder (or a different one) in a recent restore point. Do not use Windows System Restore!! But you can use a utility program to search inside shadow copies of your user data to try to locate an old file. Here are the steps:

(1) Set Windows to show hidden files and folders:

https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

(2) Download and run one of these programs:

*   ShadowExplorer: http://www.shadowexplorer.com/
*   System Restore Explorer: http://nicbedford.co.uk/software/systemrestoreexplorer/ 

Within the most recent restore points shown in the program, you can explore along this path to see whether you can find a recent shadow copy of your profile:

\Users\your-user-name\AppData\Roaming\Mozilla\Firefox\Profiles\

(3) Export any useful-looking files to a convenient location such as your currently live desktop. Then when Firefox is closed and file locks released, you can try to use them to restore your missing tabs.

Success?

In the address bar, type about:crashes<enter>. Note: If any reports do not have BP- in front of the numbers/letters, click it to submit them.

The crash report is several pages of data. We need the report numbers to see the whole report.

Using your mouse, mark the most recent 7 - 10 Submitted crash reports, and copy them. Now go to the reply box and paste them in.

For more help on crash reports, see; https://support.mozilla.org/en-US/kb/firefox-crashes-asking-support

Thanks, Fred! Here are a few of the crash report #s: bp-a0e93a52-65d3-4b43-92c7-d6aaf0200523 5/23/2020, 9:23 AM bp-5d7cf9fc-2a46-4eda-841b-4c2e80200523 5/23/2020, 9:23 AM bp-4fa424eb-6f32-4317-ac43-a45e50200523 5/23/2020, 5:10 AM bp-f6b3200f-cbde-4ce2-bac7-bb2860200523 5/23/2020, 5:10 AM bp-9c6dbc83-fbfb-409d-8397-461c80200523 5/23/2020, 5:05 AM bp-3d0c7a2d-4597-4d91-8fb0-2f3610200522 5/22/2020, 8:43 AM bp-d3980e8e-acf8-4ca2-817d-fec790200521 5/21/2020, 5:40 AM bp-dc29a56b-8ff0-456d-af14-a33b10200521 5/21/2020, 5:40 AM bp-7e4a3bed-5e0f-4ef3-9353-7bd370200521 5/21/2020, 5:40 AM bp-9a7bdc1a-0284-44fa-ae94-235cf0200521 5/21/2020, 5:40 AM bp-f0d63540-a8f5-4b0b-86b9-3d5920200521 5/21/2020, 5:40 AM bp-bdae6f6f-cc4e-4a60-b079-33add0200521 5/21/2020, 5:40 AM bp-1c6702dd-63f6-4b1b-bf62-aa1350200521 5/21/2020, 5:40 AM

bp-a0e93a52-65d3-4b43-92c7-d6aaf0200523 bp-5d7cf9fc-2a46-4eda-841b-4c2e80200523

Signature: OOM | small

MOZ_CRASH Reason (Sanitized) : MOZ_CRASH()

Crash Reason EXCEPTION_BREAKPOINT
+++++++++++++++++++++++++++++++++++++++++
bp-4fa424eb-6f32-4317-ac43-a45e50200523 Signature: OOM | unknown | NS_ABORT_OOM | IPC::ParamTraits<nsTSubstring<T> >::Read </p>

Crash Reason EXCEPTION_BREAKPOINT

bp-f6b3200f-cbde-4ce2-bac7-bb2860200523 Signature: OOM | small

nvwgf2umx_cfg.dll = NVIDIA D3D10 drivers = NVIDIA Corporation
+++++++++++++++++++++++++++++++++++++++++
bp-9c6dbc83-fbfb-409d-8397-461c80200523 Signature: OOM | small

MOZ_CRASH Reason (Sanitized) : MOZ_CRASH()

Crash Reason EXCEPTION_BREAKPOINT

klsihk64.dll = AO Kaspersky Lab

inproc_agent.dll = Kaspersky Inproc Agent
+++++++++++++++++++++++++++++++++++++++++
bp-d3980e8e-acf8-4ca2-817d-fec790200521 Signature: OOM | unknown | mozalloc_abort | mozalloc_handle_oom | moz_xmalloc | mozilla::BufferList<T>::WriteBytes

Crash Reason EXCEPTION_BREAKPOINT

IPSEng64.dll = Symantec Intrusion Detection

nvwgf2umx_cfg.dll = NVIDIA D3D10 drivers = NVIDIA Corporation

This is for Sumo's Related Bugs 1352471 RESOLVED WONTFIX Crash in moz_abort | arena_run_split | arena_malloc_large | moz_xmalloc | mozilla::BufferList<T>::WriteBytes

Update Kaspersky. If the problem continues, disable it.
+++++++++++++++++++++++++++++++++++++++++
https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

https://support.mozilla.org/en-US/kb/firefox-takes-long-time-start-up

MemTest LAST UPDATED : 27/09/2013 Could you please run a tool from http://memtest.org/ in order to check the integrity of your RAM?

You will need a thumb or disk drive to install it on.

Fred, thanks again for looking into this. I had the same problem running Norton Internet Security. Just installed Kaspersky a few days ago and it is up to date. I ran Memtest86 and no errors showed. I see references to Nvidia, but drivers are up to date as well. Task Manager shows 64% memory usage. I have 8GB memory. I am not understanding the reference to "Exception Breakpoint" - what is that saying?

I called for more help.

I am not understanding the reference to "Exception Breakpoint"

Sometimes that means memory problems.

The crash reports are OOM (out of memory) reports where not enough contiguous free memory is available and there is also insufficient space available in the Windows Page file.

Do you let Windows handle the page file or did you set a fixed size ?

If you use a fixed size for the page file then try the former and let Windows handle the page file.

I had not changed it, but when I checked it was set to fixed at 764 MB. I followed your suggestion and let the system set it, and after reboot it shows 1280. I'll see if that does the trick. Thanks for this suggestion!

That did the trick! Thanks so much for your help!