USB drive not recognized in Windows7, problem with services


New Member
I have two external USB drives, one independently-powered, one USB-cable-powered, both with NTFS and linux ext2 and ext3 partitions. Under Windows7 both drives show up under Device Manager with the Property: "A driver (service) for this device has been disabled. An alternate driver may be providing this functionality. (Code 32)". None of their partitions show up in "My Computer".

(BTW, the partitions are all good and they are all usable from the linux side of my dualboot system.)

I probably disabled the guilty service(s) myself. To get Windows7 to work reasonably, I disabled all the services I thought I wouldn't need. Which service(s) do I have to look at to get the disks to work again?

The powered disk is a Hitachi HTS545016B9A300 and the unpowered one is the internal disk from my previous laptop, a "Seagate Desktop USB Device," both as reported by the Device Manager.

Thanks much for any assistance.



Excellent Member
Microsoft Community Contributor
Do the drives show up in Disk Management? I am not suggesting initialize the drive, but you might check to see if they show as being initialized. Look at the left end near the drive letter and see if a small red mark appears or it says uninitialized.

If it is uninitialized, changing it might make it unusable with Linux--but not sure.

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New Member
No, they do not show up in Disk Management. The only place in Windows7 I've seen any evidence at all of the disks is in the Device Manager as described in my original post.

I just noticed something interesting. I had installed a version of ext2fsd which allows linux ext2 disks to appear in Windows as native - ie similar to ntfs and others. This was working a long time ago. But then I migrated my ext2 file systems to ext3 and ext4. ext2fsd doesn't support ext3 and ext4. How can I get rid of ext2fsd? Will this help?


New Member
Found the answer elsewhere. I'll report it here in case anyone finds this thread in the future.

It turns out that I needed to view the event log. In a command line enter "\WINDOWS\system32\mmc.exe eventvwr.msc" (your mmc location may vary)

In the warnings, there were a lot of warnings from Kernal-PnP. They all said that the driver /Driver/snapman failed to load. I did a web search on snapman and found out that it is a remnant of a product that I had removed from Acronis. It is tricky to remove and I followed removal instructions at

May Acronis burn in hell.....



Essential Member
I always use Revo Uninstaller to uninstall my programs.

Try going to Start ? Run > regedit and hit Enter.

Delete the following keys:
- Delete string tdrpman228 from:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318} -> UpperFilters
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{71A27CDD-812A-11D0-BEC7-08002BE2092F} -> UpperFilters

Another suggested removal process directly from Acronis:

To manually uninstall snapman.sys (as the True Image uninstaller often does not remove this driver,
which will cause a BSOD if it is installed alongside ShadowProtect), follow these steps (in this order):

1. As an administrator, run regedit.exe and navigate to
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Class\{4D36E967-E325-11CE-BFC1-08002BE10318}. Remove the snapman entry from the "UpperFilters" values. This will
unregister the snapman.sys driver as a PnP filter for disk devices.

2. Navigate to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Class\{71A27CDD-812A-11D0-BEC7-08002BE2092F}. Remove the snapman entry from the "UpperFilters"
values. This will unregister the snapman.sys driver as a PnP filter for logical volume devices.

3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\snapman and
add a REG_DWORD value named DeleteFlag with a value 1 inside this snapman key. Next,
change the Start REG_DWORD value inside the snapman key to 4 (disabled).

4. Reboot

5. After the reboot, snapman.sys will not be loaded, and its service key will be gone. You can
now delete the snapman.sys file (may be located in windows\system32\drivers directory, or in
an Acronis install directory) if you wish to do so.

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