Change the processing to foreground instead o background. You can control whether tools execute in the foreground or background by clicking Geoprocessing > Geoprocessing Options on the Standard toolbar.
The Background processing panel is where you control whether a tool executes in foreground or background mode.
If Enable is checked, tools execute in the background, and you can continue working with ArcMap (or other ArcGIS applications, such as ArcGlobe) while the tool executes. You'll see a progress bar at the bottom of your document displaying the name of the currently executing tool. When the tool finishes executing, a pop-up notification appears on the system tray. You can control how long the notification message appears by moving the Notification slider or disable the message by moving to the far left.
If Enable is not checked, tools execute in the foreground. When a tool is executing in foreground mode, you must wait until the tools stop executing before you can continue with other work.