Windows 10: Windows 10 - can be my UEFI and MBR conflict?

Also i know that UEFI firmware can emulate BIOS functionality (CSM/Legacy) and work with MBR disks just fine. So i cant understand why i get Automatic Repair during first boot, even when i change from UEFI USB KINGSTON to P1: Samsung Evo 250 GB ( like on screen on 2 page ).
So if UEFI can emulate BIOS functionality why then it get corrupted to Automatic Repair?

Still, my system works fine ( boot was: P1: Samsung Evo 250 GB ), till i change again from UEFI USB KINGSTON to P1 Samsung Evo 250 GB. So it can be a random occur?

 

Because you have to actively change the options in your BIOS to boot Legacy instead of UEFI - it doesn't switch itself automatically. It doesn't know in advance whether you are expecting it to boot from an MBR or a UEFI partitioned device. Repeated attempt to boot MBR device while BIOS is configured for UEFI boot = frustration.

 

Sorry for problem. Also i have a last question about this. Before it get corrupted to Automatic repair state in 1 boot i was switching few times without problems between UEFI USB KINGSTON to P1 Samsung Evo 250 GB and there was no Automatic repair state. It get to Automatic repair state maybe in my fifth switch. So this can happen randomly? Or issue was elsewhere?

 

I'm sorry I just don't know what to say about this last burning question. If it was booting OK from the Samsung, and it wasn't because it was with the USB still actually inserted, I'm mystified. Short of you going back where you were and actually reproducing that behavior and us analyzing what's going on, I've got nothing more to speculate on.

 

I mean before it get corrupted with Automatic Repair during 1 boot, it was working fine on P1 Samsung Evo 250 GB ( MBR ) even if i was swtiching between USB UEFI KINGSTON to P1 Samsung Evo 250 GB. It get broken after maybe my 6-six switch from USB UEFI KINGSTON to P1 Samsung Evo 250 GB ( MBR ). Sorry for my bad language , did you understand:*Smile? If you understand do you have idea why it happened after 6 my try?

 

No need to apologize for language - you're doing fine. I believe I understand what you're saying. Something has to have changed - either settings in the BIOS or configuration of the SSD or in other devices available for boot (USB drive?) to have changed the behavior you observed. I think that something is something that that neither one of us is aware of. Like I said - unless you are willing and able to go backwards and reproduce the behavior, I don't see how we'll be able to figure out the answer to your question.

 

Heh sorry . Hope you are not tired because of me. If i can ask.
You said about :"Exactly: because you were configured on BOOT screen for UEFI boot and switch to a first boot device that was NOT suitable for UEFI boot (MBR Samsung disk) and Windows was left on its own after boot failure and found an alternative means to boot. Definition of Insanity: doing the same thing over and over again and expecting the outcome to change. If you made no change in BIOS to switch to Legacy Boot, you would continually have the failure to boot 1st time and Windows finding a way to boot itself (2nd boot)."


But this switching was fine between UEFI USB and MBR SSD without problems. It happened i think on my 3 try. So if you have right , why it not make Automatic Repair on 1 try between switch, but on 3 try *Smile? Damn hope you understand *Wink. So thats why i ask about random occur if course this is issue.

 

Yes, I still understand your question the same as before - your are trying to rationalize the change in behavior for the P1 Samsung boot but I still can't say anything different than I did in post #34.*Wink

 

But after formatting to GPT and booting from BOOT MANAGER Samsung Evo 250 GB there is no issues. But i want to know why it happened before*Smile But its hard to say? I want to know if it was hardware or software issue.

 

You already have said, that you have NO issues now. You may never know what caused your problems. Be happy that your Windows is running fine, and please move on.

 

Definitely.*Nerd Reproduce it and we'll figure it out.

 

Your primary disk/SSD should be installed UEFI GPT, your storage disk any Logical Disk/SSD can be either GPT or MBR but in a UEFI system your boot Disk/SSD has to be GPT, If you want an legacy system BIOS MBR your OS disk, BIOS all have to be set to legacy BIOS MBR, Logical disk Can be either MBR or GPT if over 2 TB
On Clean Install on UEFI GPT system it is advisable to disconnect any other hard drive/SSD from your system until your have the OS Installed an booting. this prevents any chance of your boot loader writing to one of the other disk. Preventive action. The Asus Z97 boards will run MBR but you'll have to read your Manual on the board to insure your getting set up correctly. They were deigned to run UEFI GPT not Legacy MBR

 

Fair recap of everything we've already discussed in this thread, including the reference to pages 3-53 and 3-54 of the OP's Z97 user manual.

 

I had few days my system on partition with MBR and all was fine. I was booting system from P1:Samsung Evo 250 GB ( MBR ) from my UEFI and got no problem. I even switching without issues between UEFI USB and ( MBR ) SSD. But that problem happened (with Automatic Repair ) i think on my 3 try ( third switch )from UEFI USB to ( MBR ) SSD.

You said:"They were deigned to run UEFI GPT not Legacy MBR".
So maybe that was a reason of this*Smile
Also i have only one disk on my pc. This is this Samsung Evo 250 GB actually.
Also on past when i had other disk HDD 1 TB and the same my mobo with UEFI i never had Automatic Repair with Windows 7 . And Windows 7 was using MBR through my UEFI. What you think? I had installed Windows 7 by DVD .

 

Perhaps this tutorial will help you understand how to install UEFI or BIOS, BINK explains both methods very well. Word Man pointed out to you exactly where in your owner Manual this is discussed. If you don't have a manual get one here ASUS Support Downloads