Shrink volume

Can’t shrink volume C in Windows 10/8/7/Vista

Better than the old Windows XP, Windows Vista is integrated advanced functions in Disk Management to resize volumes. Windows 7/8/10 inherited the Shrink Volume and Extend Volume functionalities. Shrink Volume is very useful if you forget to edit disk drive when installing Operating System, in that case, the system C drive occupied all disk space. With Shrink Volume function you can shrink C drive to smaller size and release free space to create new drives. In Windows XP without such shrinking ability, you have to reinstall Operating System.

Actually, you can shrink C drive or any other data volumes with Shrink Volume in Disk Management. The benefit is safe and fast, however in some situations you cannot shrink volume. Searching by Google or in many forums, many people feedback the issue that they cannot shrink C drive beyond half or smaller size. In this article, I’ll explain why you cannot shrink volume C to smaller size and what to do in this situation with easy steps.

The error cannot shrink volume

The GUI and steps to shrink volume are exactly the same, so you may encounter the cannot shrink volume error in Windows 10, 8 and 7. When I shrink C drive in my laptop wihh Windows 10, I got the error message, too. What happens?

I use the default value to shrink C drive and it is the maximum available space can be shrank.

Cannot shrink C Windows 10

After clicking Shrink, I got the error message: “There is not enough space available on the disk(s) to complete this operation.”

Shrink volume error

Checking the log in Event Viewer, Event 257 shows: “The volume (C:) was not optimized because an error was encountered: This shrink size specified is too big. (0x89000021)

Error log

This error means I cannot shrink C drive to 122263MB – 100339MB, instead, I have to enter a smaller value.

In my desktop with Windows 7, I also encountered problem that I cannot shrink C drive beyond half.

Cannot shrink C Windows 7

Why you cannot shrink C drive in Disk Management

Have you noticed the tip in the shrink window “You cannot shrink a volume beyond the point where any unmovable files are located.” What does it mean?

For example: C drive is made up of 4 blocks A, B, C and D. If the unmovable files are located in block C, you cannot shrink volume to block B or A even though there is free space.

C drive block

Then what are the unmovable files? It could be Page File, Hibernation file or other files with large size. However, the “unmovable” files are identified by Disk Management. Professional partition software has the ability to move these files, so you can shrink volume C beyond half to minimum size.

What to do when unable to shrink partition

If you unable to shrink volume or cannot shrink C drive beyond half size, follow the steps below and it is very easy to solve this problem. In Windows 10, 8, 7 and Vista, there is free partition software that can finish this task well.

Step 1: Download NIUBI Partition Editor Free edition, right click C drive and select Resize/Move Volume

Resize volume

Step 2: In the pop-up window, drag the right border leftwards.

Drag to shrink

Drag to shrink

Step 3: Click OK and back to the main window, press Apply on top left to execute. C drive shrank to 30GB, actually, you can shrink it to very small size if you want.

C drive shrank

If you want to shrink a data volume to expand C drive, it cannot be done in Windows Vista, 7, 8 and 10 Disk Management, because the Unallocated space shrank from the data volume is not adjacent and behind C drive, so Extend Volume function is disabled. However, it is very easy to accomplish with NIUBI Partition Editor. This free partition software provides basic partition management to create, delete, format partition, change drive letter, etc. Advanced management to resize/move existing partition without data loss, copy, hide, set active, convert, defrag, check partition and much more.