Missing Drive letters in Disk Management Console snap-in

Issue:

There is a common issue in Windows XP and server 2003 where disk management console does not show drive letters on the partition. If you go to My Computer in Windows explorer, it correctly displays all the drive letters. The issue only occurs in the Disk management console.

Suggestion:

The issue lies with in the registry associated with the Partition manager driver (Partmgr.sys) provided in Windows. Here is the key path:

Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}
Value: UpperFilters (REG_Multi_SZ)
Value Data: PartMgr

The value data PartMgr should be present.

Please note:

• You might have other values too. DO NOT  delete them but simply add the PartMgr in the NEXT LINE.
• We need to reboot the machne after making changes
• Please back up the registry before you make any modification.

For example, on my computer I have two values:

We can also check if PartMgr.sys is indeed  present in %systemroot%\system32\drivers folder. If not, we need to replace from another machine with same Service Pack level or install an update for it.