Our client has Windows Server 2008 Std x64 running as a Hyper-V host. The client has 5 external USB hard disks, which are swapped daily as part of the backup schedule. Recently we have been investigating backup failures and found that when the USB disk is swapped, it appears in Disk Management as RAW. A simple work around is to right-click on the volume, choose "Change Drive Letter and Paths..." and then manually assign a drive letter to the USB disk. The disk then appears as NTFS and all data on the drive is accessible and works fine. The problem then recurs when the disks are swapped and we have to go through the above process over again. Not ideal to have one of our technicians doing this every day. If I connect the USB disks to any of the workstations (Windows 7) at the client site, they are fine. If I connect my Freecom USB toughdrive to the server, the same issue occurs and a drive letter needs to be manually assigned. The server is a Fujitsu TX300 S5 with twin Intel Xeon E5520 CPU's and 24GB RAM. The disks are being connected to the on-board USB ports and the problem occurs regardless of which of the ports we connect to, front or rear. Any advice, help or resolution would be appreciated. Chris

Hi Chris, Are your 5 external USB hard disks all the same brand and model? The drive will show a RAW if that partition is corrupt. This can occur if the USB pen was removed while writing data to the drive at the time it was removed. Please keep theUSB hard disk connected on server and try to run chkdsk volume: /f command to check and repair the USB hard disk. Please also make sure to update the driver for the external USB hard disks. If the problem still persists after you’ve done all that, you may copy the data over to other computer or storage devices and try to format and repartition the disks. Regards, Karen JiPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. This posting is provided "AS IS" with no warranties, and confers no rights.

Hi Karen Yes, all the external USB drives are the same make/model. We supplied them to the client when the new server was commissioned a few months ago. I have reformatted all of the disks, however, the problem persists. As mentioned in my original post, I've also tried other USB hard disks which work just fine elsewhere, but still have the same issue when connected to this server. Likewise, if I connect any of the USB disks to any other machine, they connect and work just fine. Chris

Hi Chris, Did you update the driver of those USB drives and check the disks? Regards, Karen JiPlease remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. This posting is provided "AS IS" with no warranties, and confers no rights.

Hi Karen Yes, we updated the USB drivers for those drives and also checked the disks. There were no errors reported. The issue seems to effect any and every USB drive we connect to it. At this stage, we are considering exporting the virtual machines, reinstalling the OS on the host server and then trying the USB drives again. The issue seems to effect any and every USB drive we connect to it. Chris

I have the same issue on 2003 r2 servers. When I swap the USB backup drives (each server has 2) I have to re-assign the new drive. It seemed that they worked initiially but at some point they all began acting the same way when I swapped backup drives. I have each backup drive mounted in a folder on C: called ExtBak. For simplicity I use robocopy to run the backups every day. When I swap a drive I have to delete the ExtBak folder recreate it and then use diskmanager to add the drive to the ExtBak folder. I have tried to find a best practice doc for this type of backup approach with no luck. Suggestions? Regards, Robert.

I found this note on a website for a program called USBDLM (usb drive letter manager) Windows Server Enterprise and DataCenter Edition do not assign drive letters to new fixed drives (USB and Firewire disks are usually 'fixed'). This is up to the administrator because otherwise SAN (Storage Area Network) drives might be mounted accidentally. This feature is called AutoMount and can be enabled by means of the DiskPart tool: Open a commandprompt, enter diskpart, on the DiskPart prompt enter automount to see the current state or automount enable to enable it. This was the problem for me even though my system is Windows 2008 Standard not Enterprise or DC. I have 2 windows 2008 servers with a 3 usb drive backup rotation and having to manually remap the drive (only on one of the servers) was really annoying and I knew was a problem because both didn't do it. Hope this helps you guys!