Sorry, this Support Volunteers and just us. try far right the 3 Bar Menu Restore Previous Session.

https://support.mozilla.org/en-US/kb/restore-previous-session

See solution in this post, is from above https://support.mozilla.org/en-US/questions/1185222

fyi: https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars

Please update your Flash Flash 26.0 r0 as over 100 security issues Flash Player Version: 27.0.0.187 Current Version https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

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

Restore Previous Session is the first thing to try. If it's grayed out, either the session was already restored or the file was not available/corrupted.

Either way, the next thing to check is "Recently Closed Windows" and "Recently Closed Tabs". These can be found either:

• Using the "Library" button on the toolbar, History submenu. (This button looks like some books on a shelf.)

• Using the History menu on the classic menu bar. Tap the Alt key or the F10 function key to activate the menu bar temporarily if you don't normally display it.

I also encourage you to back up all your current session history files. Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > 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 (Mac: "Show in Finder" button). This will open a new window listing your profile folder contents.

Scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Desktop or Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs.

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.bak: a backup copy of recovery.js
• 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
• various files with a .js file extension from Firefox 55 or earlier

To preview the contents of a file, you can drag and drop it onto this page, then click Scrounge URLs: https://www.jeffersonscher.com/res/scrounger.html

That tool is on my site, so please let me know if it doesn't work for you.

Any files look promising?