Disk Management no longer automatically assigning drive letters to external usb hard drives.

I use a lot of different usb hard drives in my shop. I have two basic enclosures, a generic one that uses pata drives on a usb 2.0 cable and an Apricon USB SATA 2.0 adapter.

Suddenly when I plug in a new drive device manager does see the drive and installs it in device manager. I can see the drive in Disk Management but it has no drive letter assigned, and therefore doesn't show up in Computer. I can easily just assign a letter in Disk Management and the drive immediately becomes usable. However, I would like to get Windows 7 to resume automatically assigning a drive letter.

I have tried a program called USB DriveCleanup. What it appears to have done is remove all installations of prior USB drives and when I plug in a drive that has been in the machine previously it then goes thru the install again. Yet still no drive letter. I think the program is doing what would manually be done by going into safe mode and cleaning out all the entries that build up there that don't appear in normal mode, then removes them. Basically it seems like a shortcut to manually doing it.

I also tried a registry fix that essentially asked me to delete the upper and lower filters. This seems similiar to fix for CD/DVD drives that no longer appear in Computer. This fix also didn't work.

I tried removing and reinstalling the chipset drivers. Still no go.

Running Windows 7 Pro SP1, H55 chipset.

Can anyone shed some light on this and perhaps provide a fix?


EDIT: After posting this I noticed I am not the first person to see this problem. However, no one seems to have found a cause or a fix. So, if anyone has one I would appreciate it.

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