How to extend system partition in Windows Server 2012 (R2)

It is not an easy task to many server administrators to re-size or extend system partition. Nobody would like to see system failure or data loss after doing this. Actually, it is easy and safe if you use right utility and follow the correct steps. Today I’ll show you how to extend system partition in Windows Server 2012 (and R2) without reinstalling Windows/programs or losing data. Remember, data is most important, so make a backup before any operation to a server. Select a reliable partition tool is also important to minimise the risk of server damage.

Low Disk Space in system partition

It is the most common issue in Windows platform and the reason why increasing system partition size. Different with previous version Server 2008, in Windows Server 2012, you won’t see “Low Disk Space” warning by default. Instead, when system C drive is running out of free space, it becomes red when opening My Computer or Explorer. In this situation, extend system partition as fast as possible, nobody would like to see system stuck or crash. (You may enable low disk space alert in Server 2012 when system partition is running low)

How to extend system partition

To extend system partition in Windows 2012 server, there are two kinds of tools: Windows built-in Disk Management and 3rd party partition software. Many people think that Windows native tool has best compatibility, but it’s not true. I’ve encountered the issue several times that Disk Management destroyed my partitions and data. Although there’s Extend Volume function in Disk Management, it only works under specified condition.

If you want to increase system partition size in Server 2012 (r2), you’d better run safe disk partition software. If you still want to try Disk Management, follow the method below.

Extend system drive in Server 2012 with Disk Management

From Microsoft document, to expand a drive under Disk Management with Extend Volume function, there must be adjacent Unallocated space on the right side, so you CANNOT extend system partition by shrinking other data drive. Because, the Unallocated space that shrunk from other partition is non-adjacent to system C: drive, therefore, Extend Volume is always greyed out.

The only way to extend system volume in Server 2012 Disk Management is by deleting the adjacent partition to get contiguous Unallocated space.

First of all, check your disk partition configuration if it meets the requirements:

  1. There’s at least 1 data partition with plenty of free space on the same disk.
  2. There are no programs or Windows services installed in the data partition, so you can delete it to get contiguous Unallocated space.
  3. The contiguous data drive is a Primary partition, otherwise, Extend Volume is still disabled after deleting this drive.

If your disk partition structure meets the requirements, follow the steps below, otherwise, jump to the next section.

How to extend system partition using Server 2012 Disk Management:

Step 1: Transfer all files in the contiguous partition (such as E:) to other device. Right-click drive E and select “Delete Volume…”, it will be changed to Unallocated after deleting.

Step 2: Right-click drive C and select “Extend Volume…”

Extend Volume

Step 3: Available Unallocated space is selected by default, simply click Next to continue.

Available space

Step 4: Click Finish to confirm and start extending.

Complete extending

In a short while, system C: drive is extended by adding all disk space of E drive.

partition combined
If you do not want to delete any partition, follow the methods below.

Extend system drive with safe partition software

Unlike Windows Disk Management, NIUBI Partition Editor can shrink partition and make Unallocated space on the left, then C drive can be extended easily. Your operating system, programs and anything else (except partition size) keep the same with before. Better than other partition tool, NIUBI has powerful 1-Second Rollback, Virtual Mode and Cancel-at-well technologies to protect your system and data.

How to extend system partition in Windows Server 2012 (r2) with NIUBI:

Step 1: Download this tool, right click the contiguous drive (such as D:) and select “Resize/Move Volume“.

Drag to resize

Step 2: In the pop-up window, drag the left border rightwards to shrink D drive and make Unallocated space on the left. (Another option is entering an amount behind “Unallocated space before”.)

Shrink volume

Click OK and back to the main window, as you see, 20GB Unallocated space is generated behind C: drive.

Unallocated space

Step 3: Right click system partition C and run “Resize/Move Volume” again, drag the right border rightwards to combine the Unallocated space.

Drag to resize

Hold unallocated space

Step 4: Click OK and back to the main window, click Apply on top left to execute, done!

Partition resized

Video guide to extend system partition in Server 2012 R2

If there’s no data volume on the same disk, or there’s not plenty of free space in all data partitions. No software can extend system volume by adding space from a separate hard disk. In that case, you can copy system disk to a larger one and extend partition(s) with extra disk space. If you use any types of hardware RAID arrays, do not break array or do any operations in RAID controller. If you run Server 2012 as guest virtual machine in VMware/Hyper-V, simply follow the same steps.

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