How to fix Windows Server 2012 C drive running out of space

The annoying problem in Windows Server 2012 is insufficient of disk space – the system C drive keeps running out of space, so there is not enough free space to install Windows Updates or applications. After opening Windows Explorer, you’ll find that C drive is changed to be red. When C drive becomes full, Operating System will be stuck or even crash. In this situation originally you have to start from scratch to recreate disk partitions and spend a long time to restore everything. In this article, I’ll show you easy method to fix C: drive out of space in Server 2012 (R2).

C drive out of space

The risk of C drive running out of space

When C drive runs out of space in Windows 2012 server, you’d better try to fix the issue as fast as possible, because it causes many problem such as:

  1. No free space to install critical Windows Updates.
  2. Some Windows services stop working.
  3. System stuck, reboot unexpectedly or crash.

So to solve this problem, the earlier the better.

Free up disk space on C drive

The first option to fix Windows Server 2012 C drive running out of space is freeing up disk space. You may either use Windows Disk Cleanup or 3rd-party optimization software, but I always recommend Windows built-in Disk Cleanup tool.

Note: different with previous edition, Disk Cleanup in Windows Server 2012 is disabled by default, you have to install Disk Cleanup before using.

How to fix Windows Server 2012 C drive out of space by cleaning up disk:

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 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: Open Windows Explorer, right click C drive and click Properties, and then click Disk Cleanup.

disk cleanup

Step 7: In next window, select the files you want to delete and click OK.

select files

Step 8: Redo step 7 to Clean up system files.

After these steps, you can get some free space. The C drive out of space problem can be solved temporarily. If you did not get large amount of free space, or C drive is created too small, you’d better continue the steps below to expand C drive as large as possible, otherwise, C drive runs out of free space again in near future.

Expand C drive on Windows Server 2012

With server partition software, you can reallocate more space to C: drive without losing data. That is to say, extend C drive by taking free space from other volume on the same disk. To accomplish this task, NIUBI Partition Editor is recommended. Better than other tools, it has unique 1-Second Rollback, Virtual Mode and Cancel-at-well technologies to protect system and data.

How to fix Windows Server 2012 C drive running out of space by moving free space:

Step 1: Download NIUBI Partition Editor, right click the adjacent D: drive and select “Resize/Move Volume“.

Drag to resize

Step 2: In the pop-up window, drag the left border towards right to shrink D and make Unallocated space.

Shrink volume

Or enter an amount in the box of “Unallocated space before”.

Drag to resize

Click OK and back to the main window, part of free space in D drive is changed to Unallocated on the left.

Unallocated space

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

Drag to resize

Hold unallocated space

Step 4: Click OK and back to the main window, 20GB free space is moved from D to C drive, click Apply on top left to execute, done!

Partition resized

Video guide to fix C drive out of space in fast way

If you use any types of hardware RAID array, do not break array. Follow the same steps above, there’s no difference. If the whole system disk is full, you can copy the disk to a larger and extend partition(s) with extra disk space. Besides reallocate disk space, NIUBI Partition Editor helps you do many other disk & partition management operations.

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