Solution C drive is getting full on Windows Server 2016

Updated on: November 16, 2019

This article introduces how to fix C drive full on Windows Server 2016. When system partition C is getting almost full, free up disk space and expand it larger.

The same with previous versions, Windows Server 2016 system C: drive also runs out of disk space. Many people feedback that C drive is getting almost full in a short time. To data partitions, it is very easy to transfer files or change some settings, but it is complicated to the system partition.

To many server administrators, C drive full is annoying, because Microsoft doesn't provide any solution except Disk Cleanup to free up disk space. Many people feedback that system C drive becomes full again shortly. This article introduces 3-step solution to fix C drive full on Windows Server 2016 completely.

Step 1 - Clean up C drive to reclaim disk space

It is dangerous if C drive is getting almost full, in this situation, you cannot install important Windows Updates. Server could stuck, reboot unexpectedly, the worst, you cannot boot Windows or system crash. Thus, you'd better start as fast as possible.

The first step is cleaning up C drive to reclaim disk space, then there will be some free space generated in the system partition, so this server could keep running smoothly.

To do this, Windows native Disk Cleanup is a good choice, which is easy to use, runs fast and is able to remove many types of junk and unnecessary files safely.

How to clean up system C drive in Server 2016:

  1. Press Windows and R together on the keyboard, type cleanmgr and press Enter.
  2. Select C: drive in the drop-down list.
  3. Wait Disk Cleanup utility to scan removable junk files and calculate space.
  4. Click the check-boxes in front of the files that you want to remove.
  5. Click OK to confirm and execute. (The time depends on the server performance and the amount of junk files.)

My test server is new installed, so I cannot reclaim large amount of disk space. To the servers that never or have not free up space for a long time, you may get several gigabits free space by Disk Cleanup.

Disk cleanup

However, these free space will be eaten up quickly by new generated junk files. The aim to clean up disk is getting some free space in C drive, so the server could back to the right way and you can install some programs to help solve this problem. The most important step is expanding C drive to larger size.

Step 2 - Expand C drive with free space in other volumes

The most efficient way to fix C drive full issue on Windows Server 2016 is shrinking other data volumes and add more free space to C drive.

To do this, Windows native Disk Management cannot help you, although there are Shrink and Extend Volume feature to resize disk partition. As you see in the screenshot, Extend Volume is disabled for C and E drive after shrinking D. Learn why.

The only way to expand C drive with built-in Disk Management is by deleting the right adjacent drive (D:) to enable Extend Volume feature. But in most of servers, programs and some services are running from D, so you cannot delete it.

You need to back up server and run safe 3rd-party partition software.

Cannot extend volume

Download NIUBI Partition Editor and follow the steps in the video to increase C drive free space for Server 2016:

Video guide

As you see, you can shrink other data drives in the same disk to get Unallocated space and add into C drive. To do this, you just need to drag and drop on the disk map. Operating System, programs and anything else keep the same with before after expanding C drive.

The steps are the same no matter you use physical disk, any types of hardware RAID arrays or virtual disk in VMware/Hyper-V virtual machine.

After expanding C drive, there will be plenty of free space again, this step is very important to help fix C drive full in Windows Server 2016, especially when C drive is created small or you cannot reclaim enough free space with Disk Cleanup utility.

There are other software that has similar ability, but NIUBI is the safest and fastest because it has innovative technologies to protect system and data:

Step 3 - Optimize server settings

To completely fix system C drive full on Windows Server 2016, you need the final step to optimize server settings:

  1. Install programs to separated partition such as D.
  2. To the installed programs, change the default files output path to other large partitions.
  3. Run Windows Disk Cleanup monthly to delete new generated junk files.

If the system disk is small and there is not enough free space in all partitions, you'd better replace it with larger one. NIUBI Partition Editor can help you clone disk partition to migrate Operating System and data.