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Virtual PC 2007 and differencing disk isssue

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  • Virtual PC 2007 and differencing disk isssue

    I am not sure if I am doing this right or not. If I understand it, changes to the parent VHD are saved to differencing VHD.

    I have a windows 2003 SP2 base VHD as 4GB fixed size disk. After performing windows updates/fixes, the base VHD only had about 500MB free space left. I made a copy of the base VHD and stored it in a safe area. just in case if I screw up a base, I can make another copy and work off of it. I then created a differencing disk and set a base as parent.

    Here is my problem. After I create a virtual machine (VM) using the differencing disk, I checked the C:\ drive and it showed 500MB free space, exactly what I saw in the parent disk. I downloaded 300MB file but the VM was saying I am running out of space. I thought the 300MB will go the differencing disk which dynamically expands.

    What am I missing? What is being saved in the differencing disk? Is the differencing like a partition in physical disk?


  • #2
    Re: Virtual PC 2007 and differencing disk issue

    When you create a differencing disk, it will hold the changes to the virtual machine starting that moment, and it will grow as needed.
    From the host point of view, that disk does not exist. It is an external device, managed by VirtualPC.
    So, yes, the free space on your disk will keep going down... A solution to that is to define a second HDD, and to move some data to it.
    Check in the diskmgmt.msc (on the host) that you have assigned all free space on that disk. If not, you can enlarge the existing partition...

    Sorin Solomon

    In order to succeed, your desire for success should be greater than your fear of failure.