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Windows dirs on C:, but Disk Management says System partition is D:?

Question

Thursday, June 1, 2017 7:31 AM

Hi,

I had the system disk (SSD) fail on a machine, but the identical SSD (D:) was ok, so I recently replaced the C: SSD and re-built the machine with (i thought) Windows 10 Pro installed on the new SSD (C:). 

Today when I was trying to format D:, it told me that it was unable to format the System partition. It shows as (System, Active, Primary Partition). There are no Windows directories on this drive.

C: shows as (Boot, Active, Page File, Crash Dump, Primary Partition.)

I want to re-format D: but Disk Management won't seem to let me. Can anyone explain what's going on here please?

Thanks,

GAM (Glen A McAllister)

All replies (26)

Tuesday, September 5, 2017 5:22 AM âś…Answered

Hi GAM,

I'd like to confirm:

  1. You have two SSD drives (physically two)
  2. What happens if the second SSD is removed (disconnect Power and Signal cable, if it is connected SATA port)? 

If Windows 10 can boot normally after the second SSD is removed, you can delete its partition.

You can check how is boot information (BCD information) by "EasyBCD".
(EasyBCD enables us to edit this information. But I recommend NOT to edit, editing the information would be the last option.)
 
  

Regards,

Ashidacchi

Thursday, June 1, 2017 6:44 PM

So what is disk D: now? Is this another physical disk plugged into the system? Where did it come from? Has it had Windows installed on it in the past?

Thursday, June 1, 2017 7:10 PM

Known issue in Windows 10. They no longer mandate the OS being on C:. It will run from any drive letter now.

You could try wiping both disks and removing all partitions then only create partitions on disk 0 during windows install. You could also use diskpart to assign drive letters to the partitions before the install. 

EJ

Thursday, June 1, 2017 10:07 PM | 1 vote

Hi Glen,

Could you insert a screenshot of Disk Management or share it via cloud storage such as OneDrive, Dropbox, etc?
____________
Ashidacchi

Thursday, June 1, 2017 11:34 PM

Hi,

Disk D: is one of the original 2 SSDs. It was a non-system (data-only) drive in the initial config and I did not intend to install Windows on it when I rebuilt the system. As I said in my original post, only C: (now) contains Windows directories, so I can't understand why Disk Management is saying this is a System partition. 

GAM

Thursday, June 1, 2017 11:36 PM

Hi EJ,

As I said in my original post, the OS does seem to be on C:, but Disk Management is saying D: is the System partition. This is the discrepancy I don't understand.

GAM

Friday, June 2, 2017 12:38 AM

Hi Glen,

Please try to:

  1. start Windows and check if C: is surely Windows 10 in Disk Management
  2. delete volume D: in Disk Management
    ____________
    Ashidacchi

Friday, June 2, 2017 6:57 AM

Hi, 

Here's the Disk Management window on the machine:

Regards,

GAM

Friday, June 2, 2017 7:18 AM

Hi Glen,

Thank you for screenshot.
Can't you delete D: (Disk 1) in Disk Management?
If you can, you can Create a partition and Format it after deleting.
____________
Ashidacchi

Monday, June 5, 2017 12:35 AM

Can't you delete D: (Disk 1) in Disk Management?
If you can, you can Create a partition and Format it after deleting.

Hi Ashidacchi,

No - I can't delete D:, presumably because it thinks it is a System partition. Nor can I format it.

Regards,

GAM

Monday, June 5, 2017 1:02 AM

Hi Glen,

I recommend you to delete/remove a partition by using "GParted".

  1. Download "GParted" and make a bootable USB stick
        GParted Live on USB  http://gparted.org/liveusb.php
  2. Disconnect Disk-0 (Windows drive) from your computer.  It is for not mixing up Disk-0 with Disk-1.
  3. Boot "GParted" from the USB stick (You should modify BIOS settings - boot order/sequence).
  4. delete/remove partition of Disk-1 (Extra drive).
    __________
    Ashidacchi

Monday, June 5, 2017 6:30 PM | 2 votes

Hello,

This is the way Windows NT systems described their partitions which is what disk management is showing.

System Partition equals the drive that contains the boot files.

Boot Partition equals the partition that contains the Windows folder

So do not delete either partition

Thanks, Darrell Gorter [MSFT] This posting is provided "AS IS" with no warranties, and confers no rights.

Monday, June 5, 2017 7:43 PM

After what Darrel has added (thanks for the input) I have removed my last post. I now wonder does your machine boot into Windows with the D: drive disconnected?

Monday, June 5, 2017 7:52 PM

Hi GAM,

Have you used Disk-0 and Disk-1 as RAID!(Mirroring)?

I guess that causes Disk-0 is Boot and Disk-1 is Sytem.

If this is correct, do NOT remove/delete partition in Disk-1.

____________

Ashidacchi

Monday, June 5, 2017 9:58 PM

Hi GAM,

This would be a way to move "System" from Disk-1 to Disk-0, i.e. a way to repair MBR.
0. Connect Disk-0 and Disk-1 to your computer 

  1. Boot from an installation media of Windows 10

  2. go to Command Prompt:
      2.1 Press [F8] after turning on your PC and go into the Windows Recovery Menu
      2.2 Click on Troubleshoot
      2.3 Click on Command prompt

  3. Excecute "BootRec" / type the below:
        bootrec /rebuildbcd
        bootrec /fixmbr
        bootrec /fixboot

cf. Repair Master Boot Record (MBR) in Windows
http://www.thewindowsclub.com/repair-master-boot-record-mbr-windows

If you could repair MBR (both "Boot" and "System" would be in Disk-0), a partition in Disk-1 could be removed/deleted and you could boot Windows with only Disk-0 connected to your PC.
_____________
Ashidacchi

Tuesday, June 6, 2017 6:43 AM

Have you used Disk-0 and Disk-1 as RAID!(Mirroring)?

I guess that causes Disk-0 is Boot and Disk-1 is Sytem.

If this is correct, do NOT remove/delete partition in Disk-1.

Well - I want to use RAID/Mirroring, but thought I should re-format the drive first, which is how I encountered this problem. So no - I haven't used mirroring yet.

Regards,

GAM

Tuesday, June 6, 2017 7:33 AM

Thanks for that Ashidacchi - I'll give it a go tomorrow & let you know how I went.

Regards,

GAM

Thursday, June 22, 2017 1:51 AM

Hi,

Is there any update on your issue?

Please remember to mark the replies as answers if they help.
If you have feedback for TechNet Subscriber Support, contact [email protected].

Thursday, June 22, 2017 5:33 AM

Hi,

Is there any update on your issue?

Please remember to mark the replies as answers if they help.
If you have feedback for TechNet Subscriber Support, contact [email protected].

Hi - I did try and repair the MBR as per Ashidacchi's instructions, but I'm remote from the machine and had to get someone to perform the actions and we couldn't seem to boot successfully from the Win10 installation media. It was one of those things that if I was there, I'd be ok, but I could only go on what a non-tech user was telling me.

Thanks for reminding me. I'll give it another go soon.

Regards,

GAM

Tuesday, September 5, 2017 1:38 AM

Hi,

I finally got onsite and was able to boot from the Win10 install media and perform all those bootrec actions and unfortunately, it did not seem to alter the location of the System partition, although all actions were successful. 

After re-booting, I ran the first of those bootsect commands and it also was successful, but again didn't move the System partition from D:, or add it to C:.

Thanks for your help so far. Have you any other suggestions?

Regards,

GAM

Tuesday, September 5, 2017 1:44 AM

Hi GAM,

In advance, sorry if I misunderstand your situation or environment, and sorry for my poor English.

In my memory, Windows install drive should be C drive, not other drive letters. If you do a multi-boot in your computer, it would seem other than C drive that does not boot. 
This is a screen shot of Disk Management on my dual-boot machine.

Please insert a screenshot that shows System partition is D.

Regards,

Ashidacchi

Tuesday, September 5, 2017 3:17 AM

Hi Ashidacchi,

You can reference the original screenshot I posted from Disk Management on the system in question. It is unchanged after the operations you suggested. The system is not currently dual-boot. It has all but System against C: and System against D:. C: and D: are on separate drives as you can see from my earlier screenshot.

Thanks,

GAM (Glen A McAllister)

Tuesday, September 5, 2017 4:24 AM

Thanks, GAM,

Is the issue the same as your first post (created thread)?
Can't you delete the second partition (shown as D:)?

Have you tried to "MiniTool Partition Wizard"?
It enables us to delete, move, resize partition.

Regards,

Ashidacchi

Tuesday, September 5, 2017 5:03 AM

Hi Ashidacchi,

Yes - this is the same issue, as it's unsolved (so far).

I don't want to delete D: as it contains the System partition. Wouldn't deleting that partition render the machine unbootable?

Regards,

GAM

Tuesday, September 5, 2017 11:16 PM

Hi Ashidacchi,

This was the output from EasyBCD 2.3 to confirm the problem, I think

There is one entry in the Windows bootloader.

Default: Windows 10
Timeout: 30 seconds
Boot Drive: D:\

Entry #1
Name: Windows 10
BCD ID: {current}
Drive: C:\
Bootloader Path: \WINDOWS\system32\winload.exe

I did what you suggested and disconnected the D: drive. The machine wouldn't boot - as I expected. Then I re-connected it and it still wouldn't boot! Windows was prompting me to repair Windows from my install media, which I did and the machine booted. The System partition had now moved to C:, as EasyBCD shows below:

There is one entry in the Windows bootloader.

Default: Windows 10 Pro
Timeout: 30 seconds
Boot Drive: C:\

Entry #1
Name: Windows 10 Pro
BCD ID: {current}
Drive: C:\
Bootloader Path: \Windows\system32\winload.exe

So - it seems un-plugging & re-plugging in the D: drive  forced Windows to "fix" itself. Anyway - problem solved. Thank you very much for your help. Domo arigatogozaimasu!

GAM

Tuesday, September 5, 2017 11:37 PM

Hi GAM,

Congratulations!! (Omedeto gozaimazu!!)
And thank you for marking my post as an answer.

# You might have edited "Boot Drive" by EasyBCD without removing the second SSD.
   I dared not to recommend it, since it would lead to another trouble.
   Now, you know how to use EasyBCD. The tool will be helpful in future.

Regards,

Ashidacchi

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