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

• Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/

Firefox 32 and later builds store the passwords in the logins.json file in the profile folder and no longer use the signons.sqlite file that has been used before (the matching key3.db file is still needed). If you still have the signons.sqlite file used in previous Firefox versions then you can try to force Firefox to migrate the passwords saved in that file (you will lose passwords saved in Firefox 32+ versions). You can force Firefox to reimport the passwords from the signons.sqlite file and rebuild the logins.json file with these steps:

• reset the signon.importedFromSqlite pref on the about:config page to the default value via the right-click context menu
• delete the logins.json file in the Firefox profile folder with Firefox closed

When you restart Firefox then you should have the signon.importedFromSqlite pref with the value set to true and you should have the passwords imported in the Password Manager unless there may have been errors. If that didn't help then remove or rename the logins.json and the signons.sqlite and possibly the key3.db files to force Firefox to create new files. You need to set a new Master Password after deleting the key3.db file and you lose all current passwords, so make a note if you have created any. Be sure to keep a copy of existing files before overwriting (replacing) or deleting them.

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Look on your desktop. Do you see a folder called Old Firefox?

Hi Thanks for your answers! No unfortunately I don't see any any folder on the desktop. The first answer is detailed but I'm not sure what happens if I do that because I'm not so good with the "technical" stuff...

What if just remove and reinstall it? But that won't bring anything lost back?

The browser is broken now somehow; its functions don't work anymore like they should; so not only did I lose the information saved in it but it got also clearly broken.

If your current Firefox profile folder is really broken then best would be to create a new profile and selectively transfer your current personal data to the new profile. A reset may not be a good idea in such a case because that moves the current profile and can fail if files are corrupted too badly.

You can create a new profile as a test to check if your current profile is causing 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 files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile

Hi again!

Problem solved - just decided to write if someone faces similar issue, so maybe this can help them too.

So the browser got broken and "empty" at the same time when it crashed and "froze" together with skype. And yesterday I even noticed that also my adobe acrobat writer program had some broken file in its exe (it notified me, so this crashing thing affected other files too)

Then I got a note from my laptop (windows) that a system maintenence is needed because of some broken files in the system or something like this (which had to be because of this!)

I just did the system maintenence and now it all works; the browser and all its info, bookmarks, browsing memory, etc is back again working perfectly. And this fixed the other broken files too like in adobe acrobat.  :)

So try system maintenence if something like this happens! It can be the solution.

Or I dont know if it's called "system maintenence" , but anyway, the system needed to re-organize files and fix broken files, and it fixed the problem.

That was very good work. Well Done. Please flag your https://support.mozilla.org/en-US/questions/1040079#answer-674673 post as Solved Problem so other will know.