Windows 7 - Cannot shrink volume even with free space and defrag.

[davidbuddy9]

I'm trying to shrink my main partition volume in Windows 7 in the disk management tool. I have about 50 gb of free space and I want to shave off 40 gb so I can dual boot Win7 with the latest Win10 but when I chose the shrink volume tool and it finishes checking stuff I get this:

What is the problem? I defragged multiple times and still having this issue.

 

[USAFRet]

As it says, defrag first.

 

[davidbuddy9]

As it says, defrag first.

I did, twice, says the same message. I used the disk defragmenter program that comes with Windows 7.