How to Fix: Can't Shrink Volume in Windows 7, 8, 10

Infopackets Reader Pat S. writes:

" Dear Dennis,

I am running Windows 7 and I'm trying to shrink my C drive, but Windows won't let me shrink it to the desired size - even though I have tons of free space. I have a 500 GB drive and I'm trying to shrink the volume to 250 GB. Whenever I try to shrink the C drive it only lets me shrink 70GB. Can you help? "

My response:

I have had this problem many times in the past - especially when I am trying to shrink the C drive for my clients so that I can split the drive in half and make a disk image backup onto the second partition. The reason why you can't shrink the volume to the desired size is due to a number of factors, but one of the biggest reasons is that data resides on the drive that cannot be moved because it is in use by the operating system.

I will explain how to get around that a little further down - however, I should also mention it is also possible to get around this issue by using a third party partition management utility to shrink the drive. Based on my experience, this method can be catastrophic, resulting in data loss and an unbootable system if something goes wrong. As such, my method (below) takes a little longer to complete but is much, much safer - especially if you are trying to shrink a volume remotely.

How to Fix: Can't Shrink Volume in Windows 7, 8, 10

1. The first thing you need to do is disable some services and files in use by operating system. The big culprits here are restore points (system protection), virtual memory, and system log files.
   
   To disable the system protection: click Start, then look for My Computer or This PC, then right click it and select Properties. The "System" window will appear; at the top left there is a link to System Protection - click that. The "System Properties" window will appear and the tab "System Protection" will be selected. Under the "Protection Settings" heading, click to highlight the drive you want to shrink (usually the C / System drive), then click the "Configure" button. A new window will appear with the title "System Protection for ..." (usually the C drive). Click the "Delete" button near the very bottom to delete all your restore points. When that is completed, click the button to "Disable system protection" near the top; you can re-enable it later. Close the "System Protection for ..." window and you will be taken back to the "System Properties" window - do not close it yet.
   
   Continuing on from the above: to disable virtual memory - on the "System Properties" window, and click the "Advanced" tab. Under the "Performance" heading, click the "Settings" button. The "Performance Options" window will appear; click the "Advanced" tab. Under the "Virtual Memory" headnig, click the "Change ..." button. The "Virtual Memory" window will appear; near the very top, un-check mark the option that reads "Automatically manage paging file sizes for all drives". Once you do that, the bottom portion of the window will be accessible. Highlight the drive you want to shrink (usually the C drive) near the top of the window, then tick the option for "No paging file" toward the bottom half of the window, and (!important!) click the "Set" button. Click OK to close the "Virtual Memory" window; you will most likely receive a message stating that you need to reboot the complete the changes - don't do it yet. Next, close the Performance Options window, so that the only Window you have left is the "System Properties" window.
   
   Continuing on from the above: on the "System Properties" window, you should still be on the "Advanced" tab; look for the "Startup and Recovery" section (near the bottom of the window), then click the "Settings" button. The "Startup and Recovery" Window will appear. Under the "System Failure" heading, un-check mark "Write an event to the system log", "Automatically restart", and "Overwrite and existing file", then click OK.
   
   Do not restart the computer yet.
   
   Note: after you successfully shrink your drive, you will want to re-enable all these options, so please bookmark this page and come back to it afterward.
    
2. The next thing you will want to do is check the drive you want to shrink for errors (usually the C drive). To do so: click Start, then click My Computer or This PC, locate the drive you want to shrink (usually the C drive), then right click it and select Properties. Go to the Tools menu, then under the Error Checking heading, click the "Check" button. If you have an option to automatically fix file system errors, check mark that and click OK; otherwise click the option to begin scanning. If you receive a message stating you need to reboot to scan the drive, then reboot the computer now. If you receive a message stating that there are errors on the drive, then choose to fix the errors - a reboot most likely will be required.
    
3. Reboot the computer if you haven't already in order to disable your virtual memory. Once you get back to the desktop, download and install Defraggler (free) by Piriform. It is one of the few defrag utilities on the market that allows you to defragment free space at the end of the drive which will then allow you to shrink the volume properly. Once Defraggler has been downloaded and installed, you will want to reboot into Safe Mode so that you can defrag with as few programs in use as possible, thus allowing the defrag from complete properly.
   
   To do so: click Start, then type in "msconfig" (no quotes), then click the "msconfig" utility once it appears in the start menu. Next, click the Boot tab near the top, then under the "Boot Options" heading, click the "Safe Mode" option, and then select the "network" option, and OK. Next, click Start -> Shut down and restart the computer.
   
   The computer show now boot into Safe Mode. Once you get to the desktop, double click the Defraggler utility (if it is not on the desktop, check your Start menu). Once the main Defraggler window appears, click the drive you want to shrink (usually the C drive), then go to the "Action" menu at the top left, then click the "Advanced" sub menu option, then select "Defrag free space". Once you do that, Defraggler should start moving data from the end of the drive toward the beginning.
   
   Note: based on my experience, Piriform Defraggler tends to gets "stuck" near the end of the defrag, reporting that it may still take an hour or more to complete the task, yet the blocks of data aren't being moved around as they normally would if something was actually happening. If you don't see any progress for a long time, stop the program, then reload it and watch it for about 5 minutes to see if any blocks are being moved. If nothing is happening, it is most likely finished. For the record, it's OK to have a few blocks of data present at the end of the drive even after you've defragged - your drive should still shrink properly when it comes time to shrink it.
    
4. When the drive is finished degragging, it's time to reboot into Normal mode. To do so: click Start, then type in "msconfig" (no quotes); wait for the msconfig utility to appear in the list and click it. Select the "Boot" tab near the top, then under the "Boot Options" heading, un-check mark the "Safe Boot" option, then click Apply and OK. Next, click Start, then shut down and restart the machine.
    
5. Login to the system as usual and get back to the desktop; it's now time to shrink the drive. To do so: click Start, then type in "disk management" (no quotes), wait for "Disk Management" to appear in the list, then click it. If it does not appear in the list, you can also try "diskmgmt" (no quotes) and it should work. Once Disk Management appears, locate the drive you want to shrink in the bottom half of the window (usually the C drive), left click the partition you want to shrink to highlight it, then right click over top of the highlighted area and select "Shrink Volume".
   
   Disk Management will then report "Querying Shrink Space" - this may take anywhere from a few seconds to 10 minutes to complete. When it finishes, a new window will appear asking you how much you want to shrink the drive. At this point you should now have the option to shrink the drive as much as you need. Enter in the numbers, then click OK to complete the task. The process will most likely take anywhere from 3 to 10 minutes to complete. After that is finished you should have Unallocated space near the end of the drive, which you can then left click to select it, then right click it and select "New Simple Volume" to create a new partition - if that's what you're trying to do.
    
6. When you are finished shrinking the drive, you will want to re-enable the options you disabled in Step #1, so you don't run out of memory on the system.

I hope that helps.

Additional 1-on-1 Support: From Dennis

If the above instructions are over your head, or if you are having issues shrinking your drive and you need help, you are more than welcome to contact me for remote desktop support. Simply send me an email briefly describing your problem, and I will get back to you as soon as possible.

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About the author: Dennis Faas is the owner and operator of Infopackets.com. With over 30 years of computing experience, Dennis' areas of expertise are a broad range and include PC hardware, Microsoft Windows, Linux, network administration, and virtualization. Dennis holds a Bachelors degree in Computer Science (1999) and has authored 6 books on the topics of MS Windows and PC Security. If you like the advice you received on this page, please up-vote / Like this page and share it with friends. For technical support inquiries, Dennis can be reached via Live chat online this site using the Zopim Chat service (currently located at the bottom left of the screen); optionally, you can contact Dennis through the website contact form.