Disk defragmenters running on top of Windows Vista have the potential of causing serious damage to the operating system and to your data. Programs that perform volume block manipulation during the boot process in Windows Vista are the cause of data loss, warned Microsoft. The Redmond Company has not pointed any fingers, and has failed to exemplify which applications will hurt Windows Vista, but some clues were given.

"Defragmentation programs that perform tasks early in the boot process, before the Autochk.exe program finishes, are one example of the kind of program that may experience this problem. Programs that manipulate volume blocks during the boot process, either directly or by using the FSCTL_MOVE_FILE control code, may cause data corruption or data loss in Windows Vista and in Microsoft Windows Server 2003. In this case, a drive volume may become unmountable," Microsoft informed.

According to the Redmond Company, users that deploy such programs run not only the risk of losing and compromising data in Vista but also of rendering unusable the operating system. Microsoft additionally revealed that the issue is not limited to Windows Vista and that Windows Server 2003 is also affected. The sole resolution that the company is providing for such a problem is the complete reformatting of the disk and the reinstalling of Windows.

Both Windows Vista and Windows Server 2003 "use files in the "VolumeNameSystem Volume Information" folder to store information that is related to snapshots that are created by the Volume Shadow Copy Service. These files have names that contain the following GUID: {3808876B-C176-4e48-B7AE-04046E6CC752}. When a program alters the location of blocks that are used by these files early in the boot process, data corruption or data loss may occur. This problem may also occur when a program overwrites blocks that are used by these files," stated Microsoft.