All Apple computers made in the last ten years use the OSX operating system. The interface, or the part the user actually sees, is a customized collection of commands and features. Longtime Apple users will remember the ticking watch the system used to indicate that it was deep in thought. A multi-color spinning wheel, sometimes referred to as the beach ball of death, has replaced the watch. Users encounter the wheel any time the computer must pause for a few seconds to consider the next command or action. Unfortunately, there are times when more than just a user's patience is required to stop the spinning wheel.
Use the keystroke sequence "Command+Option+Escape" if the spinning wheel does not resolve itself after 30 seconds. The resulting list of programs currently running will indicate which one is not responding. Select the offending program with your cursor and click the "Force Quit" button at the bottom of the list.
Restart the computer while holding down the "Command+S" keys if you experience persistent spinning wheels. Keep pressing until you see the gray screen with the Apple logo, then release. The screen will now be black and display lines of data. At the end of the text will be an old-fashioned computer prompt. This is "single-user "mode and allows you to fix problems in the underlying software. Type the command "fsck -y," including the space, and press "Enter." This will fix minor file errors and often cure the beach ball problem.
Open the Disk Utility program in the Utilities folder on your hard drive. Select the main drive in the window presented and click the button "Repair Permissions." This will fix aberrant behavior in some programs that have had their read/write status corrupted for some unknown reason.
A widely available free utility called AppleJack will automate and expand your capabilities in single-user mode. A corrupted preferences file can also cause the beach ball of death.
Back up your data often. Never install or remove programs when you are having difficulties; fix the problem first.