So I’m getting all set to upgrade my TIVO harddisk. I’ve downloaded and burned MFSTools, gathered all the various bits together, etc.

I thought, Hey, it’d be a good idea to try this out on a scratch HD first, just to make sure I know what I’m getting into.

So I grabbed an old 120GB drive, swapped it into my machine, and was going to reformat it as FAT32 and copy a few files on it, so act as a surrogate TIVO drive.

I swapped the drive in, restart the machine….

BOOTMGR is missing

Huh!??????

After some panicked Googling from my server, I discover that Vista has a nasty habit of writing the BootMgr sector to the “first” HD in the drive sequence according to how your BIOS is configured at the time you install Vista.

In my machine, the RAID comes pretty late in the boot sequence, so apparently, my spare 320gb drive that I was intending to use in my TIVO inadvertently picked up the Vista boot manager.

To avoid this whole mess in the first place, make sure when you install Vista, the ONLY HD that’s installed is the one you’re installing Vista onto.

However, if you’re like me, that’s not much of an option. Which leads to solution #2:

1. Shut the machine down.
2. Disconnect any “other” hd’s (other than the one that has Vista installed). If you’ve got a RAID, leave only those drives in the RAID connected.
3. Find your Vista Boot DVD
4. Put it in and restart, boot to the DVD.
5. The Vista installer will start up and ask if you want to install in English, etc. Click Next. This won’t actually start installing Vista.
6. The next screen, towards the bottom, has a “Repair your computer” option. Click it.
7. Click the operating system installation (there’s likely only the one Vista installation listed). Click next
8. In the System Recovery Options dialog, click Startup Repair.
9. Restart the computer.

Worked for me.