Newshound writes "Recently CCleaner has added an internet urban legend as a cleaning option, "Old Prefetch Data". Cleaning the Prefetch folder is an internet Myth that simply will not die due to the gross ignorance of many people in regards to how Windows XP Prefetching works. These same people generally recommend other bogus advice such as disabling Windows Prefetching completely and adding /Prefetch:1 to desktop shortcuts.
"Bottom line: You will NOT improve Windows performance by cleaning out the Prefetch folder. You will, in fact, degrade Windows performance by cleaning out the Prefetch folder.""