When you use the ADS (Automated Deployment Services) imgmount command, without the /w switch, to mount a disk image in read-only mode on Windows Server 2003 with Service Pack 1, you receive:
Data error (cyclic redundancy check)
To workaround this bug, use the /w switch to mount a copy of the image in read/write mode:
imgmount /m /w ACopyOfTheImage.img
After you are finished using the copy, you can delete it.
Microsoft Knowledge Base Article 891373, Your image may be corrupted when you try to un-mount it with the ADS Imgmount command-line tool, Describes a problem that occurs when you un-mount an image after you perform some write operations on the image. In this case, it may be corrupted.