Sorry to hear about this problem. If you don't have your normal data, could you check whether Firefox started up in a different profiles. The following article has the steps for that: [[Recover user data missing after Firefox update]]. If you had all the data except windows and tabs, you can consider the following: (A) Make sure Firefox ran a session restore (these will be hidden or grayed out): * "3-bar" menu button > History > Restore Previous Session * (menu bar) History > Restore Previous Session (B) After restore, check either: * "3-bar" menu button > History > Recently Closed Windows * (menu bar) History > Recently Closed Windows (C) If you can't get the windows back that way, back up your remaining session history files: '''(1) To open your profile folder...''' ''If Firefox is still running:'' You can open your current Firefox settings (AKA Firefox profile) folder using either * "3-bar" menu button > Help > More Troubleshooting Information * (menu bar) Help > More Troubleshooting Information * type or paste '''about:support''' in the address bar and press Enter In the first table on the page, find the '''Profile Folder''' row and click the "Open Folder" button. This should launch Windows' File Explorer listing the contents of your current profile folder. '''(2) Copy out session history files''' In your profile folder, double-click into the '''sessionstore-backups''' folder. Save all files here to a safe location such as your Documents folder. '''(3) What files did you find?''' The kinds of files you may find among your sessionstore files are: * recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session) * recovery.baklz4: a backup copy of recovery.jsonlz4 * previous.jsonlz4: the windows and tabs in your last Firefox session * upgrade.jsonlz4-''build_id'': the windows and tabs in the Firefox session that was live at the time of your last update Sometimes you can tell from the last modification time which one will have your missing tabs, but not always. '''''Optional File Contents Preview''''' These compressed files are a pain to view, so I created a tool to list out their contents. If you want to try that, you can open either of the following pages: * On my site: https://www.jeffersonscher.com/ffu/scrounger.html * On Github: https://jscher2000.github.io/Firefox-File-Utilities/scrounger.html Drag and drop a session history file onto the large box to decompress it. Then click the "Scrounge URLs" button to extract the contents into a readable format. ''If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.'' If you get a useful list, use the "Save List" button to archive it as a web page of clickable links for future reference, in case no other approach is successful. If you decide you want to roll your Firefox back to one of the older sessions, see the following articles for the steps: [[How to restore a browsing session from backup]].

Thank you, Jefferson. I'll give these a try. Jace