Use the Disk Management Tool in Microsoft Windows to shrink a hard drive volume to create room so that you can add a new partition.
Microsoft Windows provides several tools for managing the configuration of your computer and the various parts of your operating system. There are times where you will want to shrink the amount of allocated space on your hard drive, referred to as a volume, to make room for another partition. In the not-so-distant past you would have used a third-party tool for this task, but with the Windows Disk Management Tool, the utility you require is part of the operating system.
The first step is to start the Disk Management tool with elevated administrative rights. Click the Start menu button, type diskmgmt.msc into the search box, and then right-click the diskmgmt.msc entry to get to the Run as Administrator item in the context menu, as shown in Figure A.
Open the Disk Management Tool with administrative rights.
Clicking Run as Administrator will load the Disk Management Tool, which will look something like Figure B.
The Disk Management Tool will load.
As you can see, I have a recover disk on my test machine in addition to an Operating System partition and a Data partition. In general, you want to shrink a nonoperating system volume, so we will shrink the Data partition (D:).
Right-click the drive you want to shrink (D: in our example) and navigate to the Shrink Volume menu item, as shown in Figure C.
Navigate to the Shrink Volume menu item.
The Disk Management Tool will take a few seconds to analyze the drive in question and then present you with a summary screen similar to the one shown in Figure D.
The Summary shrink screen shows the results of the analysis.
The number you can change on this screen is Enter the Amount of Space to Shrink in MB box. I am shrinking drive D by 5000MB (5GB), as you can see in Figure E. Click the Shrink button when you are ready.
Shrink the drive by 5000MB.
When the process is complete, you will have a new unallocated partition. The actual size will be less than what you asked for as there will be some space taken up by the Windows file system, as shown in Figure F.
A new unallocated partition will appear.
Allocate the unallocated
The next step will be to allocate the newly created space into something the operating system can use.