Unusual behavior on your Mac may have a number of causes, but often the source is a failing hard drive. One place to check for issues is the OS X System Log, which can tell you whether there’s an I/O error that might indicate a disk issue. By using some of your Mac’s other system utilities, you may find the cause of the problem before your disk goes down completely. Jan 22 10:21:13 yourusername kernel[0]: disk0s2: I/O error The name “disk0s2” indicates the volume name. If your disk is partitioned, it’s the partition where the error occurred. Writer Bio
