If you are unable to customize a toolbar, make sure that the Allow Customizing check box in the Toolbar Properties dialog box is selected. How to allow customizing of a toolbar.
If the Toolbars command on the View menu is disabled, you might need to change the settings in the Startup dialog box or temporarily bypass its settings.
On the Tools menu, click Startup, and select the Allow Toolbar/Menu Changes check box. Close the database, and then reopen it.
You can temporarily bypass all the settings specified in the Startup dialog box instead of resetting the options. Hold down the Bypass key (the SHIFT key) while you open the database.