Hiding the "System Reserved" partition in Windows Server 2008

1. run diskpart.
2. In that program type in list vol; note the volume number for the volume with the letter you want to get rid of (it'll probably be 0 or 1).
3. type in sel vol # where # is the number you noted.
4. type in remove letter=[letter] where [letter] is the drive letter of the reserved volume.
5. use exit to exit the command window.

So a typical sequence might be:

diskpart
list vol
sel vol 1
remove letter=d
exit

Here is what seems to be your problem. As you posted:

Microsoft DiskPart version 6.0.6002  
Copyright (C) 1999-2007 Microsoft Corporation.  
On computer: ADAPP02  

DISKPART> list vol  

Volume      Ltr  Label        Fs     Type        Size     Status     Info  
----------  ---  -----------  -----  ----------  -------  ---------  --------  
Volume 0     F                       DVD-ROM         0 B  No Media  
Volume 1     D   System Rese  NTFS   Partition    100 MB  Healthy    System  
Volume 2     C                NTFS   Partition    136 GB  Healthy    Boot  
Volume 3     E   Apps         NTFS   Partition    272 GB  Healthy    Pagefile  

If I'm reading this right, you've somehow managed to get the flags swapped between the System Reserved and the actual System partition. Windows won't let you change the drive letter of the System Partition, which in this case is the wrong partition. There isn't a way to change this short of hacking the partition table directly. This was set on install.

This is actually a dangerous config, since it's probably possible to change the drive letter of the drive that has the \Windows directory on it. That's supposed to be the drive flagged System, but that patently isn't the case here. Fixing this will require reinstalling your Server 2008. Or if that's not possible, you'll just have to live with the fact that %SystemRoot% is not C:\Windows.

No I don't know how it happened. It looks like a bug to me. If you have the option, calling Microsoft about it would be a good idea.

I had same thing happen to me with Windows 10 Pro. I believe it happened after backing out a Windows Update and then applying the updates again when Windows Update installed new updates. I noticed I had a missing Windows Update as compared to my other Windows 10 Pro computer which doesn't have the problem. However, the Windows 10 Pro computer without the problem also is not a UEFI/BIOS computer whereas the Windows 10 Pro computer with the problem is. It is difficult to determine if the UEFI/BIOS is contributing to the problem but it has never been a problem before and the problem did not manifest itself until after doing a System Restore which backed out an update. And now I find I do not have the same updates as the non-UEFI/BIOS computer but this could be because a UEFI/BIOS computer could possibly take updates the non-UEFI/BIOS computer does not need.

I too tried use DiskPart to remove the Drive Letter but that too did not work. In my case the Drive Letter removed but then returned by itself later. Googling problem on the Internet also found along with the suggestion to remove the Drive Letter, it was indicated that the status of the partition may not be System but rather Utility. Using DiskPart, I couldn't exactly determine this and the documentation on changing the status seemed to indicate a certain danger when changing this status and I didn't want to take the risk. In my case I have three Partitions that shouldn't have Drive Letter but now do and they all seem to match up with the System Drive (C:) Reserved Partitions. Two of the Partitions with Drive Letters you can't do much with as they are either the wrong Disk File Format or the Partition is unformatted. So far I have been waiting for hopefully some Windows Update such as a Cumulative Update which might reinstall the missing Update to see if this corrects the problem. Otherwise, I have System Image Copies of my Windows that do go back before the change took place and I may have to experiment re-installing one of them to see if that corrects the problem and then move forward with the updates again.

Sorry, doesn't work. Gives me essentially the same error as in disk management:

Microsoft DiskPart version 6.0.6002  
Copyright (C) 1999-2007 Microsoft Corporation.  
On computer: ADAPP02  

DISKPART> list vol  

  Volume      Ltr  Label        Fs     Type        Size     Status     Info  
  ----------  ---  -----------  -----  ----------  -------  ---------  --------  
  Volume 0     F                       DVD-ROM         0 B  No Media  
  Volume 1     D   System Rese  NTFS   Partition    100 MB  Healthy    System  
  Volume 2     C                NTFS   Partition    136 GB  Healthy    Boot  
  Volume 3     E   Apps         NTFS   Partition    272 GB  Healthy    Pagefile  

DISKPART> sel vol 1  

Volume 1 is the selected volume.  

DISKPART> remove letter=d  

The selected volume is necessary to the operation of your computer.
You may not remove the drive letter from this volume.

DISKPART>  

Any thoughts?

This worked for me:

Run Disk Management Right Click on the System Reserved. Change Drive Letter and Paths Remove the letter and then restart.

Try mountvol command: mountvol Letter: /D (https://www.digitalcitizen.life/how-hide-or-dismount-partition-windows)

Also, check the partition ID or partition types: 07 = Windows NT NTFS; 17 = Hidden; 27 = OEM Recovery.

With diskpart command, first select the partition and type: DISKPART> detail partition. If it's not correct (27), change it: DISKPART> set id=27 override. Change the ID to 17 non stop the boot function work, then you can try. This not will show the letter anymore.

I know this thread is a bit old, but I found another way to do this without borking the OS.

What I wound up doing was using Partition Wizard to simply remove the drive letter and reboot the system. Even if Windows doesn't let you change or remove the drive letter assignment, Partition Wizard will override this and should work just fine provided you know that the 'System' partition is only the EFI boot information!