When the operating system needs more memory to execute the currently active programs than is actually available as main memory (RAM) in your computer, memory pages which have not been in use for some period will be temporarily removed from RAM to make room, being copied into the swap space on the hard drive. (More information about the function of the memory management is available in the chapter The Pane Diagnostics.) In Mac OS X, the swap space is implemented by one or more files located in a special folder reserved for this purpose.
In very rare cases it can be necessary to clean the swap files, e.g. when the first part of the swap space is accidentally located in a defective location of the hard drive. This is possible in single user mode because the swap space is not in use here. You can perform the steps as follows:
Cleaning the swap space does not create more room on the hard drive, because the system has to reserve the space again during next normal startup.
In some cases, a program which cannot be quit during normal operation (like the Finder or the Dock) could cause a technical problem with your computer. Such a problem becomes even more severe if automatic login of a user is active, so the erroneous application is becoming active by itself after each startup. To resolve such a problem by using a second user account, the automatic login of a user after startup can be switched off by the standalone utility.
Automatic login can be reenabled later if desired, by selecting System Preferences > Accounts > Login Options in Mac OS X.
In case you should decide for some reason to remove the standalone utility from your system, the program itself can do so. Perform the following steps to remove the application: