hello gokica, please try this in order to restore it:

1. go to firefox > help > troubleshooting information and click on profile folder/show folder. a windows explorer window should open up - in there delete the file named chromeappsstore.sqlite.
2. then enter about:config into the firefox location bar (confirm the info message in case it shows up) & search for the preference named browser.startup.homepage_override.mstone - right-click and reset that entry to the default value.
3. restart firefox

1. There was no file chromeappsstore.sqlite.

2. How to reset that entry to the default value?

I am sorry, I forget to write that after restart mozilla home page is invalid i.e. search option does not work?

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

I tried with reseting firefox many times, but with first closing and opening problem is the same. Home page is invalid i.e. search option does not work?

Check the browser.search.defaultenginename pref on the about:config page and make sure that it is set to the default value Google.

• http://kb.mozillazine.org/about:config
• browser.search.defaultenginename