eration system to search the file, which slows down system performance. In fact, defragment application moves and adjusts the positions of the files stored on disk, so operation system will search certain file more quickly, finally improving system performance. If there’s bad cluster or section on the disk, when clean up fragments, error would prompt. The solution for it is to do a complete disk scanning before this to repair disk logical error or to mark the bad track of the disk. Defragment application should not be carried out quite frequently, because when doing cleanup operation, system would frequently read the disk and consume quite a long time. If there are too many cleanups, then probably it would cause damage to the disk. Generally, once each two months is OK.