I have been fighting with this intermittent issue and spending way too much time on it. It is maddening since it will fail 3 times in a row and then succeed without any modifications whatsoever on the same hardware.
What is happening is that after the generalize pass of the sysprep run, it will install device drivers and then move onto applying system settings where it fail to parse the unattend.xml at C:\Windows\Panther saying the answer file is invalid. Looking at the unattend file, it will be truncated at the line stated in the error message.
I have tried injecting the unattend into the root of the drive, into C:\Windows\Panther with the same result. I have put waits in the provisioning template after the inject to ensure that it is being written completely. Looking at the unattend file before the generalize pass shows that the file is intact. Looking through the sysprep logs yeilds no clue as to what is happening.
I generated the unattend file with Windows Systems Image Manager and is attached below. I am on LD 9.5 SP2 trying to provision Windows 7 Enterprise SP1 x64.
Anybody know what is happening to the unattend and any suggestions on making this more reliable?