probably the restore session had some problem or you have a corrupted sessionrestore file.

Try to go to your firefox profile, enter the sessionstore-backups folder and try to first copy all the files in there to another folder and then close firefox. Now try to copy one of the older session restore backups to the sessionstore.js in the firefox profile folder and try to start firefox

if it works, great. if not, close firefox and try to restore another backup and check the results

good luck

higuita said

probably the restore session had some problem or you have a corrupted sessionrestore file. Try to go to your firefox profile, enter the sessionstore-backups folder and try to first copy all the files in there to another folder and then close firefox. Now try to copy one of the older session restore backups to the sessionstore.js in the firefox profile folder and try to start firefox if it works, great. if not, close firefox and try to restore another backup and check the results good luck

thanks for the advise, but allas it didnt work :(

I have same problem and agree that is less and less reliable, backup folder EMPTY.

So fed up with trying to fix firefox

https://support.mozilla.org/en-US/kb/update-firefox-latest-version 49.0.2

You may have corrupt sessionstore file(s). Delete all sessionstore* files and the sessionstore-backups folder.

Type about:support in the address bar and press enter.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Locate the above file. Then rename or delete it. Restart Firefox.

Several probs; recently ff slows to unusable - window darkens (ubuntu thing I know) I force quit and restart, Session Manger shows all.. it all comes back, But recent preference changes are gone - no real biggie just annoying, so next time it gets stupid I wait for it to quit on its own (so it can save changes?) Session Manager still shows all (tabs, windows - no blanks) But after restart I have 2 or 3 windows Only one of which contains a 'normal window - others are just "new tabs" and no scroll arrows, some toolbars are missing from just them too "new window" make a normal window - all accounted for ff 50.1.0; 2.33 Ghz CORE DUO, 6 G Ram. Ubuntu 16

So the problem is with your Ubuntu system? I called for more help.

See if you have any crash reports.

In the address bar, type about:crashes<enter>. Note: If any reports do not have BP in front of the numbers/letters, click it to submit them.

The crash report is several pages of data. We need the report numbers to see the whole report.

Using your mouse, mark the most resent 7 - 10 crash reports, and copy them. Now go to the reply box below and paste them in.

(Please don't take a screenshot of your crashes, just copy and paste the IDs. The below image is just an example of what your Firefox screen should look like.)

opps sorry

"No crash reports have been submitted."

Is all it says... tried it on 1 of the blank windows; nothing at all