See if these links help: https://support.mozilla.org/en-US/search/advanced?q=previous+session

I know there is a procedure that can be used to restore the previous - previous session in Firefox but it takes a lot of work. It would be greatly appreciated by lots of people if in the drop down menu at the top right of the page if there is also the option to restore the previous - previous session. I an not an IT engineer so i don't know what is involved in terms of coding but even in Photoshop there is a undo and step back options that can be clicked multiple times until you get back to the desired previous session.

Hi,

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I had a load of pinned tabs and open tabs in my last session. The pinned tabs were very important which is why I pinned them. Yesterday, I had to give remote access to a Microsoft tech and that opened another window. Later in the evening, I closed Firefox and then found this second window underneath. As you have probably guessed, I have lost everything because Firefox sees that extra chat window as my last session.

Is there any way I can recover the genuine last session please?

You should find "Restore Previous Session" in the History menu drop-down list and in the "3-bar" Firefox menu button drop-down list.

You can also create a backup of sessionstore.jsonlz4 in the profile folder and the files in the sessionstore-backups folder.

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

You will normally find these files in the sessionstore-backups folder:

• previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
• recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
• recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
• upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file with Firefox closed (make sure to backup the current sessionstore.jsonlz4).

Thank you for your reply, cor-el. The last suggestion may have solved the problem however, I noticed in another post here about the same issue that an addon exists called "Session Boss" which provides access to multiple previous sessions with a single click. After installing that, the problem was solved because it also has an export option which allowed me to install it on both my PC's and export the session from one to the other.

For what it is worth, this solution was brilliant because, although Sync allows me to copy addons to my other PC, it would not keep the sessions synchronized. Now they are! :)

Yesterday, I had to give remote access to a Microsoft tech and that opened another window. Later in the evening, I closed Firefox and then found this second window underneath. As you have probably guessed, I have lost everything because Firefox sees that extra chat window as my last session.

When that happens, immediately check one of these places:

• "3-bar" menu button > Library > History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows
• (menu bar) History > Recently Closed Windows

Or you can use the keyboard shortcut Ctrl+Shift+N to re-open the last closed non-private window.

Firefox remembers up to 3 closed non-private windows. You can increase that*, but since you use Session Boss now, it's probably not necessary.

* This preference in about:config: browser.sessionstore.max_windows_undo

Thank you for the tip. In my case it was not possible because I had closed Firefox. Only after Firefox had shut down did I see the remaining pop-up window from the Microsoft chat session.