Q: Repeated loss of drive letter assignment upon reboot

      Whenever I reboot, one of my hard drives loses it's drive letter assignment, and must be reassigned in Control Panel > Administrative Tools > Computer Management > Storage > Disk Management.

      I recently upgraded to Windows 7 Ultimate x64. I did not have this problem with the same hardware configuration and Vista Ultimate x64.


      2 250GB SATA drives in RAID 0, which contains the Windows system directory and is assigned C:
      1 1.5TB SATA drive assigned D:
      1 DVD drive assigned drive letter E:

      Upon each reboot, D: loses its drive letter assignment. I have assigning it other drive letters (such as H: or B: or G:). No drive letter assigned works.

      I am open to any solution, including running a script at boot if necessary or editing the registry. Please let me know what my options are.

      Thank you.



I know this is an old thread, but I had a similar problem, hopefully this can help others. I had an HDD drive going bad and was mounted at E:. Using software to clone the partition, when I pu the drive back in it was not being assigned a drive letter. Using Disk Management, the drive was there and I could manually assign the drive letter, but on subsequent reboots it wouldn't keep.

Rower85's post above on how he fixed it gave me the V-8 moment (smacking my head)--diskpart. Sure enough, the volume was perfectly ok, but the "hidden" attribute was set. So a quick


The next reboot assigned the drive the next open letter, so I assigned the original letter in Disk Management and did one final reboot to have the new drive (non-clicking :)) with the original drive letter.

EDIT: correct spelling of VOLUME on the first command

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1,5 year later, 1 motherboard change, contacting M$, gigabyte, seagate and nvidia and noone would help!

My solution:
Open Run and type "Diskpart"
note witch volume number that you want to autoassign on boot

Create a textfile on C:\ named: diskpart.txt
Put this in the textfile:
select volume "drive number"
assign letter="drive letter to assign"
(in the " " brackets, input your stuff, also you do not need the "")

Open Run and type notepad
Put this in:
diskpart /s c:/diskpart.txt
click File > Save As...
locate C:\ and change File Name to "diskpart.bat" then change Save as type: to All Files and press Save

Now go to Task Scheduler in the Admin section on the Control panel.
Make a new folder in the "Windows" sub folder named "Diskpart"
rightclick the "Diskpart" folder
click "Create Basic Task..."
name it to "Diskpart" and click "Next >"
select "When the computer starts" click "Next >"
select "Start a program" click "Next >"
click "Browse..."
select the "Diskpart.bat" file you saved on C:\, click "Next >"
select "Open the Properties dialog for this task when I click Finish" click "Finish"
Properties should come up, now select "Run with highest privileges"
click "OK"

And now you are done!
Sry for the noobguide ^^

Thank you Micro$oft for not solving this problem, now i would like to have all the time back i spent on manually doing this!


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Question Info

Views: 28,983 Last updated: June 9, 2018 Applies to: