As the central IT office, my group went first. I'm one of 3 people in our office that dual-boots Windows and Linux, and I was not alone as we witnessed Windows break because it was not the only operating system to control the hard drive.
Here's the process:
- We configured TPM in the BIOS, then booted into Windows. As usual to start Windows, I selected "Windows" from the Grub boot loader.
- Configured Windows to use the built-in BitLocker disk encryption. Interestingly, Windows doesn't actually complete this step, instead it needs to reboot for the change to take effect. Okay fine, it's a filesystem change.
- When I reboot, and select Windows from the Grub boot loader, Windows complains it cannot find the BOOTMGR. Unable to go on, it only lets me "Ctrl-Alt-Del" to reboot - but after rebooting, selecting Linux from the Grub boot loader still worked fine.
We mucked with it for a while, trying various Grub boot options, whatever. After about 10 minutes, we gave up, and booted from a Windows 7 recovery bootable CD. That let us run some commands from a terminal window (bootrec /fixmbr, and bootrec /fixboot) in the recovery environment, to reset the boot sector and the master boot record.
Of course, Windows seems to assume that Windows will ever be the only operating system, so the tool doesn't take any precautions for a multi-boot environment. My Linux environment was no longer usable, but at least we got Windows to boot back up.
After letting BitLocker fully encrypt my Windows data, I looked into the damage to my Linux installation. The partitions were still there, but the Grub boot selector was gone. I could have restored my Grub boot selector - I've done that before (thanks again, Windows.) But today, I thought it might be easier to just re-install Fedora 15 on my laptop, and restore my data.
Thank goodness that backup and restore is so easy in Linux. Déjà Dup has been part of Fedora for about a year. Installing Fedora 15 took about 15 minutes, then I just needed restore my data. It was easy!
And yes, re-installing Fedora also put Grub back as the boot selector. And Grub now lets me dual-boot (again) into Windows + AD + BitLocker, or into Linux.
I lost my morning to a mess caused by Windows, but regained my afternoon thanks to Linux!
But I guess my "lesson learned" is that Windows really wants to be the only operating system on the computer. Be warned.