How to reduce the size of the Windows 11 VM Disk

Discussion in 'Windows Virtual Machine' started by RicardoV6, Mar 31, 2023.

  1. RicardoV6

    RicardoV6 Bit poster

    I spent some time researching this on the Parallels forum and could not find the answer. All answers pointed to reducing usage by deleting/cleaning up files, not reducing the actual size of the drive. It turns out the reason it is not readily available is because Windows 11 encrypts the drive by default. The solution is to first decrypt the drive and then edit the VM Hard Disk settings. Detailed steps below:

    The solution from (
    • In the Windows 11 VM, open powershell or command prompt as admin.
    • Use these commands to remove bitlocker encryption:
      • Check the bitlocker encryption status:
        • manage-bde -status
      • Check the Conversion Status and Percent Encrypted values to verify that encryption is enabled
      • Disable bitlocker encryption:
        • manage-bde -off C:
      • In my case, the C: drive had encryption enabled on the space used.
      • Use the encryption status command above to check and verify when bitlocker encryption is down to 0%.
    • Shutdown and create a backup of the Windows 11 VM. Note, this isn't necessary but will protect your data in case this process corrupts the VM .pvm file.
      • Shut down the Windows 11 VM within the OS.
      • Find the .pvm file that represents the Windows 11 VM wherever it is saved in MacOS.
        • In my case, it was saved here: /Users/<username>/Library/Group Containers/<randomvalue>.com.parallels.desktop.appstore/Shared/Windows11.pvm
      • Make a copy of the .pvm file and save it in a safe place if something goes wrong and you need to restore it.
    • Open the Parallels control center.
    • Right-click on your VM and select Configure.
    • Under Hard Disk, select Advanced.
    • Select Properties
    • Resize (Reduce or Expand) the disk capacity value by either typing it in the Size field or moving the scroll bar. In my case I reduced the size to 100GB
    • Select Apply and select Continue.
    • It should resize the Windows 11 VM, then select Close, and then select OK.
    • The new size should be reflected under Disk Capacity.
    • Start up the Windows 11 VM and verify it's working.
    BarryW10, YadinF and Mikhail Ushakov like this.
  2. YadinF

    YadinF Bit poster

    You sir are a hero. I spent hours trying to figure out why 1) Parallels installs Win 11 with no option to pick a size and it sets it to 256gb, and 2) does not let you shrink the disk size after creation, only make it bigger. The fact that other threads on this issue are answered by employees that completely blow off the whole thing instead of answering any part of it is disturbing. Some serious failures in the product and support that they really really need to fix if they want people to keep using it as opposed to some free option.
  3. Pavel Merkulov

    Pavel Merkulov Parallels Team


    Thank you for your feedback.

    Let me make it clear, when you install a virtual Windows machine, the default hard drive size is 256 gigabytes.

    But that doesn't mean that the virtual machine immediately takes up 256 gigabytes of physical space on the mac's hard drive.

    The virtual machine takes up as much space on the physical disk as the files take up space in the virtual machine.

    For example, a Windows 11 virtual machine created alone, without files, only takes up 15.1 gigabytes.
  4. YadinF

    YadinF Bit poster

    Let me make it clear, that in no way addresses the issue, nor is it fully correct. It is interesting to see that Parallels is apparently doing some on the fly compression given the HDD file is 22gb (not 15) even when the VM is running when there is 27gb of data on disk. Perhaps this means they're also doing some kind of magic that no one else does (VMware, Hyper-V, Vbox) to prevent a disk image from becoming "full size" when bits are written to the end of the volume. Otherwise, 256gb could be larger than the available real space and break everything really. But the fact that it will pick this size even if that maximum isn't available is just bad to begin with, let alone not letting you pick a size because there's no way you ever want it to get that large. So once again, stop telling us this same thing over and over in these threads and actually fix the problem, and actually give a solution until you fix it (as Ricardo did since you would not). For all the marketing about this tool, not letting the user customize a VM is absurd. You want "easy" mode, fine, but give me the "advanced" button.
  5. emanuelp2

    emanuelp2 Junior Member

    You are the best this worked for me, reclaiming 182 gb of space!
  6. JonL10

    JonL10 Bit poster

    Yay! *\o/* *\o/* *\o/* I've got 100GB back that I was beginning to doubt I'd ever see again! I've been in a fruitless to and fro with Customer Support 'Engineers' (really?) for days and then chanced upon this thread. I actually only had to follow the first part (switching off encryption) and then when I went to shut down the machine it unexpectedly started reclaiming disk space without me having to reconfigure the hard disk properties : )

    Question is, what will happen if I now turn bitlocker back on, I'm wondering? I'll report back as and when I dare try it. (I'd prefer an encrypted disk, all other things being equal...)

    I've got what i wanted (finally!) which is a VM *up to* 256GB, _but not taking up 256GB when there's only 130GB on the Windows disk_
  7. JonL10

    JonL10 Bit poster

    Just to give an update, as promised above, seems like bitlocker encryption is the problem here as the size of the VM is slowly but steadily creeping back up again. - I've gained about 10GB in a working week without actually adding more than a few megabytes of files in Windows. Think I'm just going to leave encryption off after all
  8. marcol99

    marcol99 Bit poster

    I follow the
    I follow your procedures and after start up the windows 11 VM, my login profile service fail.
    I can neither attempt "forget pin" or "set up new pin" Please help!!!!!

    Here is the message:
    "Something went wrong and your PIN isn't available (status: Oxc000006d, substatus:
    Oxc0070070). Click to set up your PIN again."

    Attached Files:

  9. JacquesN1


    I simply was not able to bring my disk lower that 256Gb.
    Did everything you wrote, but in the Parallels Control Center (as directed : under Configure / Hard Disk/ Advanced / Properties) both the slider and the Size Filed would not accept anything below 256Gb.
    I am using Parallels Desktop 19...
  10. Avinash Bundhoo

    Avinash Bundhoo Staff Member

    Please collect a technical report (click Parallels icon || > Help > Send technical data > check "Attach screenshots..." > press Send Report) and send the report's 9-digit ID
    Let us. have the ID here

  11. Bachsau

    Bachsau Junior Member

    Parallels is generally not very efficient at reclaiming free space. To effectively shrink the size of a virtual disk without reducing it's capacity, you have to do the following three things:
    • Use Windows Disk cleanup to remove any temporary files
    • Run `sdelete -z C:` inside the VM to fill all the free space with zeroes
    • Shutdown the VM and run `prl_disk_tool compact --buildmap --hdd <path to *.hdd>` from the macOS terminal
    That last command will actually scan the virtual disk to find all the zeroes inside the file and remove them.
    Last edited: Apr 23, 2024

Share This Page