Windows XP Mode RC fails with “Parameter is incorrect”

So Windows 7 RTM is out. So i’ve tried playing with XP Mode, which didn’t work for me on the RC version, and after a bit of debugging didn’t find the issue.

So, with a fresh newly installed laptop and the new release candidate of Windows XP mode, i gave it a whirl again. But it failed with the same sequence of completely intelligible error messages, namely “Integration features have been disabled” and the even more helpful “Parameter is incorrect”.

xp-mode-parameter-incorrectSo i installed it on my desktop as well, where it worked without a hitch. The major difference between my desktop and my laptop is that the laptop is joined to the corporate domain and the desktop at home obviously not.

I dug a bit deeper into the event log, and drilled down to Microsoft\Windows\Virtual PC\Admin, where i found this error message:

Could not enable the Integration features for ‘Windows XP Mode’. The current mode is – 0. Last Channel start Value – 0x800700B7, Last Disconnect Reason – 0x300001B, Last Extended Disconnect Reason – 0×0, GHI State of the guest machine – 0×1

Now, this whole “disconnect” thing sounded strange until i remembered that Windows Virtual PC used RDP to deliver the screen – and at that point i thought about the RD Gateway server that’s being pushed by a GPO.

So for a quick test, i set the following key in the registry to zero:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows NT\Terminal Services\UseProxy

And tried starting Virtual PC again. It worked! Setting the key back to 1 predictably led to the same error message.

So next i excluded Windows 7 users from this GPO using a simple WMI filter, which will be a temporary measure to mitigate this issue.

This seems to be a bug somewhere, as those settings shouldn’t break Virtual PC. I’m not sure where i should report this to, but i’ll have a look at that. At least now people with the same issue should get this solution through Google.


  1. Win 7 - Virtual Windows XP - Parameter is incorrect - MCSE Forum:

    [...] [...]

  2. Tim Fisher:

    Thanks for the tip! I posted this url over on Virtual PC Guy’s blog:

    Maybe it will help some other folks. I got a different error message initially, but with this same cause.

  3. Nick P:

    Don’t know if this makes any difference, but I got the integration disabled message after installing XPM on a machine in a domain where the host machine had network drives mapped with the credentials of a domain account. The default XPM account, of course, did not have privileges to access them. Turning off the mapped drives in the “Integration Features” section of the Settings for the XP Mode VM seemed to deal with the issue.

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