SUMMARY

If Microsoft Defragmenter (Defrag) displays unmovable blocks (denoted by an "X") and you don't have any hidden system files on your disk, you probably have one of the following:

• Lost allocation units. To correct this problem, run CHKDSK /F before you run Defrag. Or, if you have MS-DOS 6.20 or higher, run Scandisk before you run Defrag.
• Executable files (.EXE or .COM files) that do not have the MS-DOS signatures for .EXE or .COM files ("MZ" or "SC"). Old executable files, shareware files, and some executable files used in copy- protection schemes do not have the MZ or SC signatures.

NOTE: Defrag looks for *DOS.* and *IO.* to find all the system files on your disk. Defrag does not move system files and represents them in the user interface with an "X."