In the event that an installation or an uninstallation of Dynamic Multipathing (DMP) fails to complete, it may be necessary to manually remove the DMP ASL components..
1. From the Windows Registry, disable vxdmp.sys by setting the start value under HKLM\System\CurrentControlSet\Services\vxdmp to "4"
2. Search for "vxdmp" under HKLM\System\CurrentControlSet\Control\Class. There should be two occurrences, both as "UpperFilters" for DiskDrive class and SCSIAdapter class.
Carefully remove the line containing vxdmp in the value part of UpperFilters entry. The other entries if any should be left. If no entries are left, delete the UpperFilter value entry itself. The exact locations in the registry are:
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318} and
HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E97B-E325-11CE-BFC1-08002BE10318}
3. Delete only DMP ASL related registry entries from the following registry locations:
HKLM\System\CurrentControlSet\ENUM\ROOT\LEGACY_VXDMPXX(where XX is the name of vendor)
HKLM\System\CurrentControlSet\Services\relative to DMP ASLs (If they exist.)
4. Reboot the server.
5. To properly remove vxdmp.sys (core DMP driver) instance from the system, run instpnp u root\vxdmp after the system has rebooted
6. Examine Enum\root and services branch to make sure the removal was successful