Fix a Dual Boot Mac that won't boot into Windows...

We have several dual boot Macs in our CIST lab that I manage and came across a problem where 3/4 of them were not booting into Windows anymore. The OSX side was fine and I could even access the Windows volume under OSX, but it just would not boot. Doing some extensive Binging (yeah, trying that out instead of Google for a change :-) I found several posts saying all you needed to do was the following:

1.) Boot from the installer CD

2.) Launch repair console DOS prompt

3.) Enter the following sequence of commands:

a.) bootrec /fixmbr

b.) bootrec /fixboot

c.) bootrec /rebuildbcd

Upon trying this on a couple of them, I still could not get them to boot. Finally, what I manage to figure out on my own, was that you needed to add to this step the diskpart command to tell it what the active partition is. We have actually have two Windows NTFS formatted partitions in our lab; one for the Windows install, and one for Virtual Machines that our used in some of the labs. So the complete repair process is as follows:

1.) Boot from the installer CD

2.) Launch repair console DOS prompt

3.) enter the command "diskpart" at the command prompt

a.) ***Note: you can type "help" at any time while in the diskpart menu to get a list of possible commands

b.) type "list disk" to show all disks in the system

c.) type "select disk #" where number is the number of disk you need to view

d.) type "list partition" to see what partition number you need to make active (the one that Windows is actually installed on)

e.) type "select partition #" where number is the number of the partition that you need to set active

f.)type "active" This should activate the currently selected partition so that the following commands know what partition to set as the bootable volume

4.)bootrec /fixmbr

5.)bootrec /fixboot

6.)bootrec /rebuildbcd

With any luck, if you have a similar setup like ours, your macs will once again boot into Windows. Since figuring this process the rest of the Macs have started exhibiting this problem and had to have this fix applied. So, I can only think that some Windows or Mac update is what caused the problem, but do not know which for sure.