Extend System C Drive on Windows Server 2019

by Andy, Updated on: August 19, 2020

This article introduces how to extend C drive in Windows Server 2019 without losing data, detailed steps to extend system partition C for Server 2019.

When system C: drive is running out of space, you can increase its partition size without reinstalling Operating System and applications. When there is free unused space in other partition on the same disk, you can add these space to expand C drive. This article introduces how to extend C drive partition in Windows Server 2019 without losing data.

1. Use right tool to extend system partition for Server 2019

Windows Server 2019 native Disk Management utility has built-in Shrink Volume and Extend Volume functionalities to help re-size allocated partition. However, this native tool cannot extend C drive by shrinking D or other drives. Unallocated space that shrunk from D is nonadjacent to C drive, so Extend Volume is greyed out when you right click C drive.

You can get adjacent Unallocated space by deleting drive D to enable Extend Volume for C drive, but in most of servers, programs and some Windows services are installed to this partition, so you cannot delete it. In addition, under some particular environment, you still cannot extend C drive after deleting D.

How to extend C: drive partition in Windows Server 2019 Disk Management:

  1. Move all files in the contiguous partition D: (E in some servers) to other place.
  2. Press Windows and X together on your keyboard and select Disk Management in the list.
  3. Right click D: drive and select Delete Volume, then its disk space will be converted to Unallocated.
  4. Right click C: drive and select Extend Volume, click Next till Finish in pop-up Extend Volume Wizard.

Tips while extending system partition C in Server 2019 Disk Management:

  1. Unallocated space deleted from a partition must be next to C drive and on the same disk.
  2. If the contiguous partition D is Logical, its disk space will be changed to Free instead of Unallocated. This kind of space can't be added to C drive.
  3. It is not 100% safe. The same with third party software, there is potential system damage and data loss risk while resizing volume.

Why there is such kind of risk? To be short, all parameters of associated disk, partition and files must be modified correctly when resizing disk partition. Some software internal error and hardware issue such as power failure could cause part of the parameters failed to be modified. If it happens, system and/or data will be damaged. So make a backup in advance and run safe partition software, otherwise, you'll lose data or waste a long time to restore everything.

Better than other disk partition tools, NIUBI Partition Editor is much safer and faster because of the advanced technologies:

2. How to extend C drive by shrinking D or other partition

In most of servers, there's free unused space in other data partition(s) on the same disk, you can shrink the one with plenty of free space, then part of free space will be changed to Unallocated and all files keep intact. Finally add Unallocated space to C drive, then there will be more free space in C drive again. In this way, Operating System, programs and anything else keep the same with before. To accomplish this task, you just need to drag and drop on the disk map.

Download NIUBI Partition Editor and you'll see the main window with disk partition structure and other information on the right. Available operations to selected disk or partition are listed on the left and by right clicking. Unavailable operations are hidden automatically to keep interface clean.

Steps to extend C: drive partition in Windows Server 2019 with NIUBI:

  1. Right click the contiguous partition on the right (D: in most cases) and select "Resize/Move Volume". In the pop-up window, you may either drag left border towards right or enter an amount in the box of Unallocated space before. Then drive D will be shrunk and some Unallocated is generated on the left side.
  2. Right click system C: drive and select "Resize/Move Volume" again, drag right border towards right to merge this Unallocated space, then C drive will be extended.
  3. Click Apply on top left to execute, done.

Video Server 2019

  • If your right contiguous partition is E, simply replace D with E in the steps above.
  • If you want to shrink nonadjacent partition, there's an additional step to move Unallocated space before adding to C drive. (Method is shown in the video above).
  • NIUBI is designed to work in virtual mode first, real disk partitions won't be changed until click Apply to confirm. If you did anything wrong, simply click Undo to cancel.
  • The pending operations that are marked as Check can be done in Windows, the one marked as Refresh requires rebooting to accomplish.
  • When there's available free space on the same disk, there's no difference to expand system C drive, no matter you use physical disk, any types of hardware RAID with any raid controller, or run Server 2019 as guest virtual machine in VMware/Hyper-V.

3. How to extend C drive partition with another disk

As I said above, there must be available free space on the same disk, then what to do if the system disk is almost full? In that case, no software can expand C drive by taking free space from another different/separated disk. However, you can solve this problem by copying disk to a larger one. Follow the steps in the video to extend C drive partition in Windows Server 2019 with a larger disk:

Video Server 2019

As you see, additional space can be added to C drive and other partitions. Note: you should start from the last one to move and extend partition.

4. Expand C drive volume for Server 2019 in VMware/Hyper-V

If you run Windows Server 2019 as guest virtual machine in VMware, Hyper-V, Virtualbox or other tool, there's no difference when there's available free space on the same virtual disk. You just need to install NIUBI Partition Editor to the virtual machine and follow the steps in the first video above.

If the virtual system disk is almost full, you can expand it with VMware or Hyper-V. After expanding disk, additional space is shown as Unallocated on the end.

In Summary

To extend system C drive in Windows Server 2019, firstly check your disk partition structure and configuration, then follow the corresponding method above. Remember to make a backup and run safe partition software. Because of the advanced data protection technologies, NIUBI Partition Editor is the best choice to accomplish this task. Besides shrinking and extending partition, it helps do many other operations for your server.