Portable document formats are useful for sharing information in a single format independent of variables between users' computers. Documents aren't subject to word-processor settings, but are easy to open and view in their correct appearance using the Adobe Acrobat program. Sometimes, the program malfunctions and doesn't close when you try to exit. The fix for this problem is simple, whether you're using a PC or Mac.
Press the "Ctrl," "Alt" and "Delete" buttons on your keyboard simultaneously if you're using a Windows computer. This command, known as Control-Alt-Delete, opens the Windows Task Manager, a list of all programs currently running on your computer.
Select the "Applications" tab. Select Adobe Acrobat from the list and click "End Task."
Press the "Cmd," "Opt" and "Esc" buttons on your keyboard simultaneously if you're using an Apple computer. This command opens the Force Quit menu.
Select Adobe Acrobat from the list. Click "Force Quit."