Error message when you specify the value of the InstallToAvailablePartition XML element as "true" in the Unattend.xml file to install Windows Vista: "Windows could not prepare the computer to boot into the next phase of installation"

Consider the following scenario:

• You try to use an unattended answer file (Unattend.xml) to install Windows Vista.
• To do this, you specify the value of the InstallToAvailablePartition XML element as "true" in the Unattend.xml file.
• The computer does not have an existing system volume. For example, there is no valid active partition on the boot disk.

In this scenario, you may receive the following error message during the installation of Windows Vista:Note The InstallToAvailablePartition XML element is in the following section of the Unattend.xml file:

To resolve this problem, use one of the following methods.

Method 1

Set a partition to be active. To do this, follow these steps:

1. Open the Unattend.xml file by using a text editor such as Notepad.
2. In the Unattend.xml file, locate the DiskConfiguration XML element, the Disk XML element, and the ModifyPartitions XML element.
3. Under the ModifyPartitions XML element, set a partition to be active by typing true in the Active XML element. For an example, see the following sample code:

   <DiskConfiguration>
      <Disk>
         <DiskID>0</DiskID>
         <WillWipeDisk>false</WillWipeDisk>
         <ModifyPartitions>
            <ModifyPartition>
               <Order>1</Order>
               <PartitionID>1</PartitionID>
               <Active>true</Active>
            </ModifyPartition>
         </ModifyPartitions>
      </Disk>
   </DiskConfiguration>
   

4. Save the file, and then exit Notepad.

Method 2

Set the InstallTo XML element to specify an explicit partition where you want to install the Windows image. Do not specify the <InstallToAvailablePartition> XML element. To do this, follow these steps:

1. Open the Unattend.xml file by using a text editor such as Notepad.
2. In the Unattend.xml file, locate the ImageInstall XML element, the OSImage XML element, and the InstallTo XML element.
3. Under the InstallTo XML element, specify an explicit partition where you want to install the Windows image. To do this, type the partition number in the <partitionID> XML element. For an example, see the following sample code:

   <ImageInstall>
   	<OSImage>
   		</InstallFrom>
   		<InstallTo>
   			<DiskID>0</DiskID>
   			<PartitionID>1</PartitionID>
   		</InstallTo>
   		<WillShowUI>OnError</WillShowUI>
   	</OSImage>
   </ImageInstall>
   

4. Save the file, and then exit Notepad.

Method 3

To resolve this problem, make sure that there is a valid system volume before you use the Unattend.xml file to install Windows Vista. For example, make sure that there is a valid active partition on the boot disk.