Converting from Dynamic to Basic disks

One of the worst blue screens of death you can get is a stop error on boot 0x0000007b which is an inaccessible boot device. One of the reasons that can cause this is trying to convert your boot disk to a dynamic disk which can cause you these types of problems. Unfortunately, there is no supported method of switching a disk from dynamic to basic and you need to hack the disk into thinking it is basic. This situation came up this past weekend when attempting to use Acronis Disk Director to increase the size of a particular partition on the system disk. When the server rebooted, the stop error happened. When attempting to boot into safe mode or last known good configuration, the same stop error occurred. Fortunately, we found an article at:

http://thelazyadmin.com/blogs/thelazyadmin/archive/2007/01/17/Converting-Dynamic-Disks-Back-to-Basic-Disks.aspx

that talked about how to modify particular sectors on a disk (01CO for the C partititon, 01D0 for the D partition, etc) and change the third byte from a 42 (indicating a dynamic disk) to a 07 (indicating a basic disk). The tool described in the article only works inside of Windows and does not work from a boot disk. Fortunately, a copy of Hiren's boot cd includes a copy of Norton Disk Editor which allows you to boot your dead system, modify the sectors for each partition, write the changes back to the disk, and then boot. This worked flawlessly and allowed the system to boot properly. Just make sure that you modify the byte for each partition on the disk that you want to convert back to a basic disk and your system should be fine.