The World According to Mitch

I have used Hyper-V for as long as there has been Hyper-V.  Today I use it much less than I once did, but it is still handy for running VMs on my laptop.  I run a particular VM called ‘Sandbox’ in which I do all sorts of things that I would not want to do on my live system… things that I can simply try and then wipe.

When I built the Sandbox VM I was spending a lot of time at home, and portability was not a huge issue.  I ran it on one of my external drives, and it worked fine.  I allocated 100GB and was good to go.

When I realized I was going to be on the road again I could just as easily take my external hard drive with me, but the shortage of USB ports on my Surface Pro meant making a decision… I was going to shrink the VHDX file and put it on my internal hard drive.

76GB free space.  That’s going to be a problem.

Step 1: Shrink your partitions

My 100GB virtual hard drive (.vhdx file) meant that somewhere within the VM I had a 100GB partition (or at least a few partitions that added up to that).  I had to shrink as much as I could.

1. If you have a Pagefile.sys, Swapfile.sys, and Hiberfil.sys you should eliminate them now.  Remember that even if you turn off Memory Paging the files don’t disappear until you reboot.
2. Defragment the disk.  We may not talk much about it anymore, but the old faithful defrag.exe C: still works. 
3. Use the Disk Manager console to shrink your C: as much as you can… but not too much.  When I tried it I had the option to shrink it down to 11.5 GB… I’m pretty sure that would render my VM pretty useless.  Pick a number that works for you.  I chose 60GB.
4. Using the diskpart tool delete any partitions at the end of your drive.  I had a 450MB Recovery partition on mine.

Because it was a Recovery (read: SYSTEM) partition I needed to do the following:

Select Partition 5

Delete Partition OVERRIDE

Good… Now we can shrink the VHDX file.

In the older versions of Hyper-V this would have meant shutting down the VM.  You don’t have to do that anymore… but you do have to run PowerShell as an Admin.  Once you do:

Step 2: Shrink your VHDX file

The cmdlet is easy…

1. Navigate to the directory where you keep your VHD file;
2. Resize-VHD -Path .\Sandbox-PC.vhdx -SizeBytes 60GB

It will only take a minute and you will be done.  Simple as pie!