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 :
- Download and install the free AOMEI Backupper Standard
- Take an image backup of the entire disk0 on an external disk, as explained
in the article How to Backup Disk.
- Create Aomei Bootable CD/DVD or USB Flash Drive as explained in the article
How to Create Windows PE & Linux Bootable Disc.
- 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 :
- 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:
- Move D: to the end of disk1
- Copy all the partitions of disk0, in their order, to the beginning of disk1,
so they are immediately followed by D:
- Move partitions so the unallocated space follows C: and resize it to include this space.
- 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.
- Boot from the new disk0. If this does not works, you will need to
Fix Windows 10 Master Boot Record.
- 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.