Relocate Visual Studio Package Cache

Aug 30, 2016  

Visual Studio stores lots of data into %ProgramData%\Package Cache (in my case over 10GB worth of data). Fortunately, Heath Stewart provides a step-by-step procedure of how to move the contents of the folder into a VHD.

Update procedure for my Windows 7 machine

The following is an update procedure taken from Heath’s blog post. I’ve added the missing \ and updated the paths to match my configuration:

  1. Open an elevated command prompt.
  2. Run diskpart.exe to start the disk partitioning utility:


  3. Create a large (ex: 1TB), expandable VHD on whatever secondary disk (for instance on Q:\Disks) you prefer with security matching the source directory’s security:

    create vdisk file="Q:\Disks\Cache.vhd" type=expandable maximum=1048576 sd="O:BAG:BAD:PAI(A;OICIID;FA;;;BA)(A;OICIID;FA;;;SY)(A;OICIID;FRFX;;;BU)(A;OICIID;FRFX;;;WD)"

  4. Select the VHD and create a partition using all available space:

    select vdisk file="Q:\Disks\Cache.vhd"
    attach vdisk
    create partition primary

  5. Format the volume that was created automatically and temporarily assign a drive letter (for instance T):

    format fs=ntfs label="Package Cache" quick
    assign letter=T

  6. After exiting diskpart.exe, move any existing per-machine payloads from the Package Cache with security:

    robocopy "%ProgramData%\Package Cache" T:\ /e /copyall /move /zb

  7. Recreate the Package Cache directory and set up the ACL and owner as before:

    mkdir "%ProgramData%\Package Cache"
    echo y | cacls "%ProgramData%\Package Cache" /s:"O:BAG:DUD:PAI(A;OICIID;FA;;;BA)(A;OICIID;FA;;;SY)(A;OICIID;FRFX;;;BU)(A;OICIID;FRFX;;;WD)"

  8. Run mountvol.exe without any parameters first and look for the volume name that has the drive letter you assigned to the VHD, then use that with mountvol.exe again to mount that volume into the empty Package Cache directory.

    mountvol "%ProgramData%\Package Cache" "mountvol "%ProgramData%\Package Cache" \\?\Volume{0e930327-6da7-11e6-8211-d8a25e8438ad}

  9. Run diskpart.exe again and remove the drive letter assignment from the volume (should be in partition 1 of the VHD):

    select vdisk file="Q:\Disks\Cache.vhd"
    select partition 1 remove letter=T

  10. Non-boot VHDs are not automatically mounted, so before you reboot you need to make sure the VHD is mounted again whenever the machine is started. Write a simple script for diskpart.exe to execute on startup. If you’re doing this on a laptop, you should edit the scheduled task afterward to allow it to run on batteries.

    echo select vdisk file=Q:\Disks\Cache.vhd > Q:\Disks\Cache.txt
    echo attach vdisk >> Q:\Disks\Cache.txt
    schtasks /create /ru system /sc onstart /rl highest /tn "Attach Package Cache" /tr "%SystemRoot%\System32\diskpart.exe /s Q:\Disks\Cache.txt"

Additional notes

To detach a VHD using diskpart.exe:

select vdisk file="Q:\Disks\Cache.vhd"
detach vdisk

To attach a VHD using diskpart.exe:

select vdisk file="Q:\Disks\Cache.vhd"
attach vdisk

To unlink the Package Cache folder from the VHD:

mountvol "%ProgramData%\Package Cache" /D

To link the Package Cache folder with the VHD:

mountvol "%ProgramData%\Package Cache" \\?\Volume{0e930327-6da7-11e6-8211-d8a25e8438ad}


The volume ID will be different from the one mentioned in my examples, as it gets assigned when the volume gets first created by diskpart.exe.