IMO, use '''Bookmark All Tabs ...''' for each of those 8 windows separately to get them into your Bookmarks; and then synced onto the new device. Make sure you label each of those folders, like maybe "Window 1 Tabs" or such. Then when Sync has been run on the new device right-click each of those folders of Bookmarks and use '''''Open All in Tabs'''''. Then open a new window and do the same with the 2nd saved folder of Bookmarks; continue until all 8 windows or tabs are open on the new device. ------------------ '''MozBackup''' extension would ''(IMO)'' work better than Sync for populating a new device with an exact copy of what you are now using. http://mozbackup.jasnapaka.com/ ''MozBackup is a simple utility for creating backups of Mozilla Firefox, Mozilla Thunderbird, Mozilla Sunbird, Flock, SeaMonkey, Mozilla Suite, Spicebird, Songbird and Netscape profiles. It allows you to backup and restore bookmarks, mail, contacts, history, extensions, passwords, cache etc.'' -------------------------------- An alternative method ''(for mid to advanced computer users)'' would be to not use Sync or MozBackup, but rather copy your entire Firefox Profile over to the new device and then copy / paste the individual files and folders that are inside the current Profile folder ''(that was created the first time Firefox was run on the new device)'' into the new Profile, replacing any existing files. https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile ------------------- I have never used MozBackup ''(been doing it manually since before I was even aware that MozBackup existed or before it was created)'' and Sync doesn't really synchronize extensions too well. If you have a good number of extensions installed that save their own data in Firefox or have a lot of settings / configuration parameters, you may have a lot of work to do getting everything "just so" after using Sync. ''And some extensions have hidden about:config parameters that need to be enabled to "sync" - documentation is spotty at best or requires a lot of digging thru about:config to find those preferences.'' I built a new PC in May 2015 and used Sync to get it set up. 'Right off the bat' I discovered extensions missing; extensions that I forgot weren't hosted by Mozilla; 3 out of 42 extensions had been installed from the developers own website and weren't available from Mozilla. '''''My bad''''' - forgot that Sync doesn't actually "synchronize" extensions, it installs then fresh from the Mozilla Add-ons server. Then over the next few days I discovered that some data saved by extensions and many preferences for extensions didn't get "synced"; wasted a lot of time running into the other room to the old PC and copying extension data files piecemeal as I discovered yet another extension not working as I had it setup on the old WinXP box. After about a week of that I 'threw in the towel' and just copied the old WinXP Firefox Profile over to the new Win 7 box, to stop the 'bloodletting' and restore my sanity. ------------------- '''tl;dr''' ''conclusion'': '''YMMV''' If you have a lot of time invested in customizing ''(extensions & custom preferences)'' Firefox don't count on Sync to duplicate your current setup on the new device. MozBackup or a "manual job" will work better to accomplish your goal.