Often, customers encounter Windows startup failures (the infamous "blue screen") after performing configuration changes to a virtual machine which are not allowed for an already installed Windows operating system. Depending on the presence of several hardware features, the Windows installation program chooses special kernel and device driver versions and will fail to startup should these hardware features be removed.

Most importantly, never disable ACPI and the I/O APIC if they were enabled at installation time. Enabling them for a Windows VM which was installed without them does not cause any harm. However, Windows will not use these features in this case.

When installing Windows 2000 guests, you might run into one of the following issues:

These problems are all caused by a bug in the hard disk driver of Windows 2000. After issuing a hard disk request, there is a race condition in the Windows driver code which leads to corruption if the operation completes too fast, i.e. the hardware interrupt from the IDE controller arrives too soon. With physical hardware, there is a guaranteed delay in most systems so the problem is usually hidden there (however it should be possible to reproduce it on physical hardware as well). In a virtual environment, it is possible for the operation to be done immediately (especially on very fast systems with multiple CPUs) and the interrupt is signaled sooner than on a physical system. The solution is to introduce an artificial delay before delivering such interrupts. This delay can be configured for a VM using the following command:

VBoxManage setextradata VMNAME
           "VBoxInternal/Devices/piix3ide/0/Config/IRQDelay" 1

This sets the delay to one millisecond. In case this doesn't help, increase it to a value between 1 and 5 milliseconds. Please note that this slows down disk performance. After installation, you should be able to remove the key (or set it to 0).

When Windows guests run into a kernel crash, they display the infamous bluescreen. Depending on how Windows is configured, the information will remain on the screen until the machine is restarted or it will reboot automatically. During installation, Windows is usually configured to reboot automatically. With automatic reboots, there is no chance to record the bluescreen information which might be important for problem determination.

VirtualBox provides a method of halting a guest when it wants to perform a reset. In order to enable this feature, issue the following command:

VBoxManage setextradata VMNAME
           "VBoxInternal/PDM/HaltOnReset" 1        

Unfortunately, with Vista, Microsoft dropped support for the virtual AMD PCnet card that we are providing to virtual machines. As a result, after installation, Vista guests initially have no networking. VirtualBox therefore ships a driver for that card with the Windows Guest Additions; see Sectioná4.2.4, “Windows Vista networking”.

Starting with version 1.6.0 VirtualBox can emulate an Intel E1000 network device which is supported by Vista without any third-party drivers.

Several background applications of Windows guests, especially virus scanners, are known to increases the CPU load notably even if the guest appears to be idle. We recommend to deactivate virus scanners within virtualized guests if possible.