Back and forward or other toolbar buttons are missing or disappeared in Mozilla FireFox Browser

This article describes how to restore Firefox's default toolbar configuration if the Back button, Forward button, or other toolbar buttons are missing.

Showing the Navigation Toolbar

If you can't see any of the toolbar buttons (Back, Forward, Reload, Stop, Home) or the Location bar, you may have the Navigation Toolbar hidden. Click the Firefox View menu, select the Toolbars sub-menu. If there is not a check mark next to Navigation Toolbar, click on it to put a check mark by it.

If showing the Navigation Toolbar does not restore your missing buttons, continue to the next section.

Restore the default toolbar set

To put the toolbar buttons back into their default places:

1. Click the Firefox View menu, and then select the Toolbars sub-menu, then click the Customize... item to open the Customize Toolbar window.
2. Click Restore Default Set
   
   
   
   
3. Click Done to dismiss the Customize Toolbars window.

The default toolbar buttons should now appear in their default locations. If you would like to rearrange your toolbar items, see How to customize the toolbar. If your toolbar buttons are still missing, continue to the next section.

Reset toolbars and controls

If the above methods fail to restore your toolbar buttons:
First, start Firefox's Safe Mode:

1. Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Exit menu item.Close down Firefox completely: On the menu bar, click the Firefox menu, and select the Quit Firefox menu item.Close down Firefox completely: At the top of the Firefox window, click the File menu, and select the Quit menu item.
2. In Windows, click Start, open the All Programs list, and navigate to the Mozilla Firefox folder. In the Mozilla Firefox folder, select Mozilla Firefox (Safe Mode).Hold down the Option key, as you start Firefox.Go to your Terminal and run:

   firefox -safe-mode

   You may need to specify the Firefox installation path (e.g. /usr/lib/firefox-3.5).
3. Firefox should start up with a Firefox Safe Mode dialog.
   
   Note: You can also start Firefox in Safe Mode by clicking Start, selecting Run (or use the Start Search box in Windows Vista) and then entering the following in the text field:
   

   "%PROGRAMFILES%\Mozilla Firefox\firefox.exe" -safe-mode

4. Check mark Reset toolbars and controls.
5. Click Make Changes and Restart to restart Firefox
   
   
   

The default toolbar buttons should now appear in their default locations.

SOURCE:SUPPORT.MOZILLA.COM