Are there any browser.sessionstore.* prefs that appear in italic and have a locked state?

You can reset browser.sessionstore.* prefs that are user set (bold) to the default value via the right-click context menu on the about:config page to make sure that Session Restore is enabled and working properly.

• http://kb.mozillazine.org/Session_Restore
• https://support.mozilla.org/kb/restore-previous-session

all sessionstore values are default (not italic or bold). the windows_undo is 3, the tabs_undo is 10

With those pref set to the default values should Session Restore work and History > Recently Closed Tabs/Windows should show tabs and windows that have been closed.

Make sure that you do not run Firefox in (permanent) Private Browsing mode (Never remember history).

• https://support.mozilla.org/kb/Private+Browsing

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

firefox is set to "remember history" so its not in permanent private mode

like i said, new installation with a new profile, so it cant be the profile

not exactly sure whats causing this

just tried installing the current beta (version 27) as a longshot, but still the same issues, I've also noticed i cant open new tabs from my back and forward buttons either (using middle click)

something is definitely wrong with some settings in firefox...

You can still try to use the Profile Manager to create a new profile.

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

when i reinstalled it, it made a new profile so that's not the issue here

the problems in the links provided have to do with bookmarks not saving and the toolbars not functioning at all

my firefox is not having problems with bookmarks, the back button works fine, i just cant open items in my back/forward history in new tabs. the recently closed tabs is permanently greyed out and doesn't function, the firefox homepage search doesn't work and i'm guessing other features are probably broken

uninstall and reinstall (new profile) did not help, neither did upgrading to the beta, virus scan found no viruses

They also have to do with history problems and thus can affect session restore (places.sqlite stores history and bookmarks).

thats true, but i already tried a new profile (with the reinstall) which would have made a new places.sqlite file as well and that didnt fix the issue

after uninstalling firefox, removing all traces from the registry and installed drive, running numerous scans from malware, spyware and anti-virus programs and even scans from registry cleaning programs, i found that there were no issues with my computer

i then tried installing an old version of firefox (v20) hoping it would solve the issue, to my surprise, everything was finally working! so i updated back to v26 and nothing worked like above! then i tried downgrading to v25 and again everything worked!

from that i can gather that the issue was NOT with my profile, extensions, plug-ins, settings or anything of my doing, this is an issue with firefox 26 and above!

if anyone is having similar problems, i would recommend installing a previous version of firefox and seeing how that works, disable auto updates if that helps with the issue

Normally problems with restoring tabs and windows would have to do with the sessionstore.js file that either doesn't get created or is corrupted somehow.

If the sessionstore.js does get created,but you still can't restore closed tabs then try to validate the file.

• JSON Formatter & Validator: http://jsonformatter.curiousconcept.com/

Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

as i said before my issues were continuing after numerous clean uninstalls (which remove the profile and create a new one) and even after upgrading to beta versions, its VERY unlikely that the sessionstore.js file was getting corrupted every single time... also as i stated in my original post, the problems were not limited to tabs/windows

this is clearly an issue with firefox 26 and the higher (beta) versions like i said v25 works fine, but then v26 does not

this was NOT an issue with the profile or sessionstore or any values within the about:config settings

For me, it was TabMix Plus causing this error with FF26 and FF27. I simply installed TMP v.0.4.1.3 and it was completely solved - no need for any other measures in my case.

The problem is mentioned here: https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/, as is the v.0.4.1.3 download link.

never used that add-on, also when i reinstalled firefox i removed all traces including add-ons

Hey not sure if it has been fixed for you but I had this problem after updating to 29.0. I realise you completely reset/reinstalled everything so this might not fix it but all I had to do was Clear all browsing data(Ctrl+Shift+Del) and then use 'Exit Firefox' from the drop down menu(not the window's top right close button)

For whatever reason that fixed it and I can now restore sessions/restore closed tabs.

Wow, thank you. Clearing history and exiting from the dropdown menu fixed my problem as well. It was the second thing I tried (the first thing I tried was checking about:config where the 2 relevant settings were at their defaults) and it worked. :)