[SOLVED] Windows will only boot from Windows Boot Manager?

May 3, 2020
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So I was just hanging out playing minecraft on my PC today when all of the sudden a huge thunderstorm came rolling by. The Power flickered for a second and it causes my PC to reset twice. My PC is plugged up to a Serge protector. Thought Okay no big deal the power just went out. But now when I boot my computer normally it keeps giving me a message "Missing operating system" and will be stuck on that screen. Not good. So I tried to reset and go into boot settings. When I hit use Windows Boot Manager it boots right up no problem, at least that I've seen so far. I reset the computer to test it. Still loads up to "missing operating system."


I now tried to go into BIOS and change the boot order. I was normally loading off of my SSD. I changed the boot order from SSD first to Windows Boot Manager first. Computer now boots up like normal.

Is it okay to keep using windows boot manager to start my PC? Why is my computer suddenly not able to boot from SSD like it normally has? I have checked health on my SSD and it looks good. Once PC is booted everything works. Normal transfer rates. all my data still there.

Just trying to make sure nothing got fried in the thunderstorm. Should I be trying to get my boot back to SSD or just leave it on windows boot manager?
 

Colif

Win 10 Master
Moderator
Some motherboard bios have the ability to swap boot methods on restart if the PC doesn't find a boot device. Its possible the 2 resets you did tricked it into swapping to the other one.

Windows Boot manager is basically just a launcher. It should have the partition address of the boot drive saved inside it so if you only have it and ssd in PC, it would be pointing at that anyway. It is used to launch boot drives.

MBR drives and GPT drives are booted differently
In MBR systems, the bios only looks on the 1st partition of the drive to find the boot partition, If it doesn't find one, it goes to next drive, or throws an error.
In GPT systems, the boot partition can be anywhere on the disk so it uses the Windows Boot Manager to locate the right place on the drive.

If you try to boot a GPT drive in legacy settings, it won't boot it.
If you try to boot a MBR drive in UEFI settings, it might actually work as UEFI is backwards compatible - it had to be as it was replacing a standard that had been in place for decades. Windows Boot Manager can be used for both.


Background info
Up until 2009 all PC used what we now call Legacy bios. These supported MBR disk format. (MBR = Master Boot Record). Every version of WIndows until Win 8 defaulted to MBR.
Legacy bios had a number of shortcomings:
  • Legacy bios didn't have any idea what a mouse was, so everything was kb driven
  • Difficult to add new features
  • Restrictive max size
  • MBR disks can only have max of 4 partitions and Max disk size is 2.2terrabytes
Leading up to 2009 a consortium of hardware makers got together to fix limitations of both the legacy bios and MBR
UEFI (Unified Extensible Firmware Interface) was created to replace Legacy.
It can be updated
and knows what mouse does (there are other advantages I am just being basic)
GPT drives can have up to 256 partitions on a drive and max drive size is 18.8 million terrabytes
WIn 8 & 10 default to GPT.
GPT = GUID (Global Unique ID - Every drive on earth has its own unique number) Partition Table
 
Last edited:
May 3, 2020
2
0
10
0
UPDATE: I tried going into start up repair and got a message saying startup repair could not fix my system.
UPDATE2: So I went back into BIOS and loaded a saved profile from last known good boot. Which changed boot order to SSD first and Boot Manager second. Reset and now PC seems to be working like normal.

Not 100% sure what happened but it seems to be working now.
 
Last edited:

Colif

Win 10 Master
Moderator
Some motherboard bios have the ability to swap boot methods on restart if the PC doesn't find a boot device. Its possible the 2 resets you did tricked it into swapping to the other one.

Windows Boot manager is basically just a launcher. It should have the partition address of the boot drive saved inside it so if you only have it and ssd in PC, it would be pointing at that anyway. It is used to launch boot drives.

MBR drives and GPT drives are booted differently
In MBR systems, the bios only looks on the 1st partition of the drive to find the boot partition, If it doesn't find one, it goes to next drive, or throws an error.
In GPT systems, the boot partition can be anywhere on the disk so it uses the Windows Boot Manager to locate the right place on the drive.

If you try to boot a GPT drive in legacy settings, it won't boot it.
If you try to boot a MBR drive in UEFI settings, it might actually work as UEFI is backwards compatible - it had to be as it was replacing a standard that had been in place for decades. Windows Boot Manager can be used for both.


Background info
Up until 2009 all PC used what we now call Legacy bios. These supported MBR disk format. (MBR = Master Boot Record). Every version of WIndows until Win 8 defaulted to MBR.
Legacy bios had a number of shortcomings:
  • Legacy bios didn't have any idea what a mouse was, so everything was kb driven
  • Difficult to add new features
  • Restrictive max size
  • MBR disks can only have max of 4 partitions and Max disk size is 2.2terrabytes
Leading up to 2009 a consortium of hardware makers got together to fix limitations of both the legacy bios and MBR
UEFI (Unified Extensible Firmware Interface) was created to replace Legacy.
It can be updated
and knows what mouse does (there are other advantages I am just being basic)
GPT drives can have up to 256 partitions on a drive and max drive size is 18.8 million terrabytes
WIn 8 & 10 default to GPT.
GPT = GUID (Global Unique ID - Every drive on earth has its own unique number) Partition Table
 
Last edited:

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