MS-DOS 7.10 Knowledge Base (Article C3) -------------------------------------------------------------------------------- How to defrag my drives under DOS? Last updated on: February 17, 2004 -------------------------------------------------------------------------------- The information in this article applies to: MS-DOS 7.10 SYMPTOMS After installing MS-DOS 7.10, when you type DEFRAG under MS-DOS 7.10, you may receive the following message: Note: DEFRAG has been disabled to support Long File Names and FAT32 drives. CAUSE There could be Long File Names (LFN) on your drives, especially when you have Windows 9x/Me/NT/2000/XP+ installed on your system. However, there isn't a DOS DEFRAG tool that supports LFN so far. Therefore, if you use some older defrag tools (e.g. DOS6 DEFRAG) that are incompatible with LFN, then they could and will destroy many/all existing LFN and cause data loss on your drives probably without any notifications or warnings. Also, the existing defrag tools for DOS don't support FAT32 drives, so you cannot use them to defrag your FAT32 partitions. In order to protect the existing LFN and FAT32 drives, DEFRAG has been disable in MS-DOS 7.10. RESOLUTION In fact, you don't need to defrag your drives in most cases. Furthermore, using defragmenters too often may cause drive fault sometimes, especially on some older hard drives. Thus, don't try to do so unless you have to. The real solution for this DEFRAG problem is the existence of DEFRAG for DOS that works with both FAT32 drives and Long File Names (LFN). Unfortunately, there isn't such a tool so far. But in order to defrag your FAT12/16 drives with or without Long File Names (LFN), you can try DEFRAGD.EXE from ROM-DOS 7.10, which does support and won't destroy LFN. Please never try to use the old defrag tool from MS-DOS 6.x or so if there are any Long File Names (LFN) or FAT32 drives on your system, since MS-DOS 6.x DEFRAG could harm your system because of the reasons mentioned above, no matter what version of the DOS you are using. On the other hand, ROM-DOS 7.10 DEFRAG works fine under MS-DOS 7.10 with LFN. Therefore, under DOS, this is the best one for you. To use it, just download and copy DEFRAG.EXE to the MS-DOS 7.10 path, and then type DEFRAG under DOS to execute it. Still unfortunately, this defrag tool doesn't work with FAT32 drives yet. For FAT32 support, please read the information below. MORE INFORMATION The defragmenters included in Windows 98/ME/2000/XP+ fully support Long File Names (LFN) and FAT32, so you may defrag your drives if you have any of them available. If you only have MS-DOS 7.10 with Windows 3.x or Windows for Workgroups 3.x, that's fine too, because DEFRAG.EXE from Windows 98/ME will work even in Windows/WFW 3.x with only a small change. Here you can download the FAT32 and LFN aware version of DEFRAGW.EXE, which will work great in Windows/WFW 3.x! Please feel free to use it since it is totally FAT32 and LFN compatible. In addition, if you have or find any DOS DEFRAG tool that supports both LFN and FAT32, please let me know, thanks! Return to MS-DOS 7.10 Support and Troubleshooting Section C