I was working with a new client recently who was interested in trying out Team Foundation Server. As MSDN subscribers, they downloaded the trial version of the TFS CD and had it sitting on the desk ready for me to install. I kicked off the install as I’ve done many times but unfortunately the installation kept failing. It soon became apparent that their CD was the problem. They assured me that they had only downloaded it a few days before and it should be fine. As it turns out the CD was not fine and they had managed to burn a corrupt disk image.

So how can this be easily avoided?

1. Copy down the checksum value from the MSDN download site when you grab the ISO.
2. Check this value once the ISO has been downloaded using a tool like HashCalc or similar. SlavaSoft’s HashCalc is a great little freeware utility that does many things including calculate the CRC Checksum (SHA-1 HASH) that Microsoft displays on the MSDN Subscriber download site.
3. When you burn the image, don’t use the maximum buring speed of your device. I always turn it down to about half just for good measure for images I particularly care about.
4. Use the verify feature on your burning software to confirm that there have been no errors while writing the disk.

These steps might take a few extra minutes but it is usually nothing compared to the time wasted with corrput disks/ISO images.

Here’s a screenshot showing the SHA-1 Hash on the Microsoft MSDN Subscriber website as well as a screenshot of the result in HashCalc.