I use Windows 10. How do I add the yellow partition to the red one, to increase the size of red? Green (833 GB) must be left alone and should not be changed or moved.

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Self-condemnation: In hindsight, when I was initiating my laptop on Windows 10 after buying it, I really should have allocated more than 100 GB to C. Sigh.

  • 3
    You can't use a hard drives containing a Windows installation to create a spanned volume. It's a bad idea anyway as spanned drives don't provide fault tolerance — if one drive fails you will lose the data on all hard drives.
    – DavidPostill
    Sep 27, 2016 at 21:40
  • See How to combine multiple hard drives into one volume on Windows 10 for more information.
    – DavidPostill
    Sep 27, 2016 at 21:41
  • @DavidPostill Sorry, I do not understand your previous comment. I do not wish to combine all of Disk 1 to Disk 0, only the yellow 97 GB; I am not touching the green 833 GB.
    – user269574
    Sep 30, 2016 at 14:44
  • 1
    I already said, it it not possible.
    – DavidPostill
    Sep 30, 2016 at 16:47
  • @Timere you can move data to free some space on system drive without creating spanned volume. This includes Program Files, see superuser.com/questions/390636/… Oct 6, 2016 at 15:19

4 Answers 4


I will not repeat the explanation why it is not possible to merge the system partition with another disk. Instead I will treat the poster's basic problem, which is : Given his partition setup, how can he enlarge his C: system partition?

First step : Backup

When modifying partition layout, the smallest mistake can destroy the disk pr render the computer unbootable. Therefore the first step must be to take a backup of disk0.

I counsel :

  1. Download and install the free AOMEI Backupper Standard
  2. Take an image backup of the entire disk0 on an external disk, as explained in the article How to Backup Disk.
  3. Create Aomei Bootable CD/DVD or USB Flash Drive as explained in the article How to Create Windows PE & Linux Bootable Disc.
  4. Boot the above CD/DVD or USB Flash Drive and ensure that it can see the above-created backup file on the external disk.

Once this is done, you can be reasonably sure that you can now recover from any mistake, but better to still be very careful.

I list below three possible solutions to the system-drive space problem. You will need a third-party Partition Editor tool, since Windows Disk Management will not let you manipulate sensitive partitions. I counsel using the free AOMEI Partition Assistant Standard Edition.

Solution 1: Add 20 GB to the system disk

This solution is the safest, and if it works out then nothing will change in your use of your computer.

The disk0 layout shows two Recovery partition and one OEM partition. The 20 GB partition is probably for Windows 10, although by all accounts it should take at most 500 MB.

The Recovery partitions ensure that Windows can boot into its recovery environment if it cannot boot normally. You have two because the second one was added by the upgrade to Windows 10.

This solution entails using the AOMEI Partition Assistant to reduce the 20 GB Recovery partition to a more modest size such as 1 GB, moving both it and the other 1000 MB Recovery partition to the right, so as to form an unallocated space just after C:.

However, if AOMEI cannot resize this partition, then move on to Solution 2.

You could also safely delete the OEM partition, whose purpose is for doing a factory-format on the computer, thus returning the computer to its state when it was manufactured.

I would use Windows Disk Management to extend C: over the reclaimed space.

Solution 2: Add 22 GB to the system disk

This solution is by removing both Recovery partitions and the EFI partition and extending C: over the reclaimed space.

Recovery partitions can be deleted if you have a bootable version of Windows. You will be giving up the convenience of recovering from boot errors by booting into this environment from the disk, and instead will need to boot from a recovery media.

See the article Creating a Recovery Drive (USB) for a detailed description of the process. In a nutshell : Type Windows-key+R and enter RecoveryDrive.exe to start creating the recovery media. After the process is complete, you’ll be asked if you want to delete the recovery partition, which you accept. Then use AOMEI Partition Assistant to delete the other Recovery partition and the EFI partition. I would use Windows Disk Management to extend C: over the reclaimed space.

Guard carefully the recovery media, in case it will be needed in the future.

Solution 3: Add much more to the system disk

This is the most complicated, which entails :

  1. Reducing the size of disk D: so that the unallocated space at its end will equal the size that you wish to allocate to C:
  2. Move D: to the end of disk1
  3. Copy all the partitions of disk0, in their order, to the beginning of disk1, so they are immediately followed by D:
  4. Move partitions so the unallocated space follows C: and resize it to include this space.
  5. Open the computer case and exchange disk0 and disk1. Only the connectors need to be exchanged, if possible, without the need for taking out the disks.
  6. Boot from the new disk0. If this does not works, you will need to Fix Windows 10 Master Boot Record.
  7. The old disk0, which has now become disk1, can be formatted and used as an additional partition of 119 GB.

This is the most cumbersome solution, leaving you with a larger disk C:, a smaller disk D: and a new disk E:, so might not be your preferred solution. It also requires a careful backup of the contents of D: before starting.


The C: drive is your primary drive with the Operating System on it.

When you change a basic disk to dynamic, you will be able to create volumes that span multiple disk such as spanned and striped volumes.

However a basic disk uses a regular partition table deployed by Windows, whereas a dynamic disk allows for noncontinuous volumes between drives.

Meaning to say that Windows will not run/install on a dynamic drive as it does not employ the records required to start Windows.

Hence you will not be able to span your volume dynamically between the two drives without affecting your current installation of Windows.

For further reading about dynamic and basic drives.


To be able to span you volume across multiple disks, you'll have to convert it to a dynamic disk.

See: https://technet.microsoft.com/en-us/library/cc731274(v=ws.11).aspx

Once you do this you should be able to expand it to the second disk.

Edit: As user @ DavidPostill said though, this can be a bad idea in some cases as if you lose one disk, you lose everything.

  • 3
    And it's not possible with the physical disk that contains the partition that is home to the system drive.
    – Jeter-work
    Sep 30, 2016 at 16:11

To create a spanned volume in Windows:

Back up any data on your drives, since you'll need to erase the ones you're spanning.Open the Start menu and type diskmgmt.msc. Click on the option that appears and find the disks you want to combine.If your disks have data on them, right-click on each and choose "Delete Volume." Make sure you're deleting the correct volumes!counter(item).Right-click on the first of the now-empty drives you want to add to your span and choose "Create New Spanned Volume".When the New Spanned Volume wizard starts, click Next until you get to the Select Disks screen. Highlight the second disk you want to add to the span, then click the Add button. Continue this process until all the disks you want are on the right size of the selection wizard, then click Next.Assign your spanned volume a drive letter, then click Next. Format it as NTFS and give it a name. When it's finished, you're ready to use your new spanned volume.

It can be risky as others have already suggested. You may end up with losing data of C drive. Without affecting other drives you can't directly add this unallocated space to C.

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