What to do when C drive is getting full in Windows Serve 2012?

The same with other Windows operating system, in Windows Server 2012 the system C drive is getting full after running the server for a period of time. When C drive becomes full, try to fix this issue as soon as possible, otherwise, there is no free space to install critical Windows updates, some Windows services stop working, server stuck or even crash.

When C drive is almost full in Windows 2012 server, it changes to be red after opening Windows Explorer. Unlike other versions, low disk space alert is not enabled by default, so you’d better pay more attention.

C drive full

To fix Server 2012 C drive full issue, there are many methods but following two are the fastest:

  1. Clean up disk to reclaim free space
  2. Increase C drive space by moving from other partition

1. Clean up disk to reclaim free space

To free up space on C drive, you may use Windows native Disk Cleanup utility, 3rd-party software or delete files manually. I recommend use Disk Cleanup, because it is safe to delete most of junk files. If you are not familiar with Windows Server 2012, do not delete files manually.

To use Windows Disk Cleanup:

Different with other Windows editions, in Windows Server 2012 Disk Cleanup is disabled by default. To use it, you should enable it by yourself.

How to fix C drive full issue with Server 2012 Disk Cleanup tool:

Step 1: Click Server Manager on bottom left, click the 2nd option “Add roles and features“.

server manager

Step 2: Click Next till you see the Features.

Add roles

Step 3: Click the check-box in front of “Desktop Experience” and click Next.

Select to install

Step 4: Within several minutes, the installation complete, click Close.

Install complete

Step 5: Restart the server to finish adding features.


Step 6: After booting to desktop, right click C drive in Explorer and click Disk Cleanup.

disk cleanup

Step 7: In next window, select the files you want to safely delete. After the freeing up complete, you may redo step 6 to Clean up system files.

select files

After these steps, you can reclaim disk space more or less. If you got large amount of free space, congratulations! If you got little free space, or the C drive was created too small, you’d better continue the steps to expand C drive, otherwise, you’ll see Server 2012 C: drive full in near future.

2. Increase C drive free space

As long as there is free unused space in other volume on the same disk, you can increase C drive by moving the free space. To accomplish this task, a safe disk partition software is very important, because there’s potential system/data risk with unreliable tool.

Step 1: Download NIUBI Partition Editor, right click the adjacent partition on the right (here is D:) and select “Resize/Move Volume“.

Drag to resize

Step 2: In the pop-up window, drag the left border rightwards or enter an amount in the box behind “Unallocated space before”.

Shrink volume

Drag to resize

Click OK and back to the main window, D drive is shrunk and Unallocated space is made on its left. A pending operation is also added on bottom left.

Unallocated space

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

Drag to resize

Hold unallocated space

Step 4: Click OK and back to the main window, Unallocated space is added to C drive in virtual mode, click Apply on top left to take effect, done!

Partition resized

NIUBI Partition Editor has unique Roll-Back protection technology, which is able to roll back the server to the status before resizing automatically and rapidly even if power failure or any other hardware issue occur. Furthermore, it is 30% – 300% faster than any other tools, because of its unique file-moving algorithm.

Video guide to fix Server 2012 C drive full issue in the fastest way

Besides resizing partition and increase C drive free space, NIUBI helps you do many other disk & partition management operations.

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