When running a Prepare for Image Capture Task, Sysprep appears to hang and doesn't complete. The Windows\System32\Sysprep\Panther\setupact.txt file contains an error about an invalid unattend.xml
When a Prepare for Image Task is created the unattend.xml in the NSCap\bin\Win32\x86\Deployment folder becomes part of that task in the database. If the unattend.xml in the NSCap\bin\Win32\x86\Deployment folder was customized improperly or otherwise corrupt, when a Prepare for Image Capture task is created then this instance of the Prepare for Image Capture task will always fail.
To resolve this issue, restore or replace the existing unattend.xml file in the NSCap\bin\Win32\x86\Deployment folder with the one provided by Symantec as part of the Deployment Solution installation. Then delete your non-functional Prepare for Image Capture task and create a new Prepare for Image Capture task.