Dynamic disks support limited partition types, which constitute extended partitions, OEM partitions and type 0×42 for dynamic volumes. If the disk MBR or EBR contains another partition type value, it might render the disk to exhibit improper behavior. These errors are also observed when MBR or EBR is corrupted, compelling you to recreate the disk partitions. If the backup proves inefficient in such cases to restore data, you need to apply partition recovery utilities to scan and restore them.

For example, when you view the disk in Disk Management snap-in, it might appear as

“Dynamic Unreadable”

When you right-click the disk to change it to basic disk, you receive the below message:

“Data on the this disk will be lost if you convert the disk to Basic, do you wish to continue?”

Clicking ‘Yes’ to this error doesn’t help as you come across an hour glass for some time and the operation fails. If you choose to use Diskpart.exe utility for converting the disk, it gives the success message, but the disk still appears with ‘Dynamic Unreadable” status.

These errors are specifically observed with Windows Server 2003, XP and 2000 based systems.

Cause

Such errors primarily occur because of following reasons:

MBR contains few partition table types

MBR is incorrectly altered

MBR or EBR is damaged. In such cases, MBR or EBR contains the hexadecimal 0×42 as one of the partition’s system ID, which refers to dynamic disk

Solution

To troubleshoot such issues, you should follow these measures:

Use Dmdiag.exe or Diskmap.exe utility in verbose mode to check for invalid system IDs. Doing so will output the MBR information in hexadecimal format. You can change the invalid partition type value to ‘0×42′.

If the problem continues, you need to to use Diskpart.exe tool or clean command with Dskprobe.exe to delete all the existing partitions. This allows the disk becoming a basic disk. Restore the data from backup

At times, situations arise when restoring from backup is not feasible. Backup might be absent or invalid. In these conditions, you are recommended to use partition recovery software. Built with advanced scanning technology, these tools perform safe and comprehensive partition recovery.

Stellar Phoenix Windows Data Recovery Services reliable and fully-competent utility designed to recover lost and deleted partitions for Windows 7 RC1, Vista, XP, 2003 and 2000 based systems. It is a non-destructive partition recovery software providing advanced and impressive set of features. The tool supports complete recovery of data for FAT32, VFAT, NTFS and NTFS5 file system drives.