Error starting any VM when VirtualBox is started as non-admin user

[Neno Ganchev]

When VirtualBox.exe is started by a user that has no administrator privileges on a 64-bit Windows 7 host all VMs fail to start (they don't even get to loading the BIOS). The following error message appears in a VirtualBox - error dialog:

Failed to open a session for the virtual machine 2008R2.

The version of the device registration structure is unknown to this VBox version. Either mixing incompatible versions or the structure isn't correctly initialized. (VERR_PDM_UNKNOWN_DEVREG_VERSION).

Result Code: E_FAIL (0x80004005)
Component: Console
Interface: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6}

The problem is present for old and new VMs alike. Last tried with a clean install of VirtualBox 4.3.10 and a newly created VM.

The problem disappears when VirtualBox.exe is started as an administrator.

[Klaus Espenlaub]

In this case it's an outdated/incompatible "D:/dev/virtual-kd/VBoxKD64.dll" which is configured manually for your VM.