Windows Boot Manager won't boot the correct drive

TheAntColony said:

Supposedly UEFI has benefits though, right?

Although it's not 3 decades old like BIOS is, it's not really all that new. They've been working on it since the late 90s; it just hasn't really made it into the wild quite yet. It was almost two years ago when I first noticed that a few OEMs had EFI in big box stores.

In addition to supposedly quicker boot times and greater boot media security, this from Wikipedia:

• Ability to boot from large disks (over 2 TB) with a GUID Partition Table, GPT.
• CPU-independent architecture
• CPU-independent drivers
• Flexible pre-OS environment, including network capability
• Modular design

A few links to peruse:

https://en.wikipedia.org/wiki/Extens...ware_Interface

Say Goodbye To Your BIOS: Hello, UEFI! : On the Verge Of UEFI

UEFI - About UEFI

HTG Explains: Learn How UEFI Will Replace Your PC’s BIOS - How-To Geek

Demystifying UEFI, the long-overdue BIOS replacement | ExtremeTech

As I thought, no problems mixing UEFI and MRB installs. Something on your install may have a problem. Not sure if it might the bios itself, or the actual install.

You can check my bios Boot options. Since it will default to the MBR install if the UEFI one is not available, possibly yours is doing that.

Still would like to see a picture of your Disk Management window. But at least, you can compare yours to mine.

I notice Disk1 which appears to be MBR disk has no System label. Does this mean it is being booted off of the EFI System partition? Or is it booted via BIOS Boot Menu key?

The EFI partition is the System partition and was booted to.

Had I booted MBR, of course, the other 100 mb partition would have been system.

So you can boot directly to the MBR disk in BIOS boot menu at boot?

Yep, all I do is select the drive you can see in the bios pictures.

These are two separate installs. If you had two separate MBR installs, would it not work the same way with a boot option for each install? Each install would have its own active partition that showed as System when booted into that install...

Actually two distinct MBR installs on separate HD's should have each have a System Active flag on the partition holding boot files. It's when they are both booting off one that it is the only one to hold the System flag. Yet sometimes they will both still boot independently via the BIOS Boot order and/or BIOS Boot menu key.

It isn't likely that an EFI System partition could also boot an MBR disk, is it? Just askin.

Saltgrass your return here is just in the nick of time. We are facing retooling all of our install and repair procedures for EFI even in the midst of still handling more of these types of cases than all other forums on the web combined.