Windows 10: Stuck in UEFI after reset to default.

What is the present situation?

If CSM (Legacy BIOS) is enabled, then the partition table you posted in post #3 (MBR) is perfect. BIOS-MBR is a perfect combination.

If you disable CSM, set all the values to UEFI first, and try to install Windows in a MBR disk, it will be problematic. In this situation, you need to run the windows installer as UEFI ....

• wipe the HDD (as you stated in post #9),
• Put the installer (USB or DVD),
• Restart the computer,
• Hold the "boot menu key" during POST,
• When the boot menu will appear, guide it to the UEFI option (there will be two options, UEFI and without UEFI) using the scroll keys,
• Let the installer partition the HDD.

If you do it, it will be partitioned to GPT automatically.

But, If you do it, you will loss the D drive, too.

Now, if you want to keep the D drive intact, get the PW Boot CD (as the C drive is there in the same HDD, the installed version of PW will not do the operation). Follow it: How to Convert MBR Disk to GPT Disk | MiniTool Partition Wizard Tutorial
When done, delete C and System Reserved. Boot into the windows installer as UEFI (as stated earlier). Install Windows in the free space. Let the installer create the other necessary partitions.

All are done. You will be another perfect combination, UEFI-GPT.

 

Thanks a lot @Arc.

But the question is that I can't do that, I have no choice.

I burn the W10 iso to the pendrive with the Micrisoft tool (W7 USB DVD Download Tool is called) and I can't install it when it is GPT partition system or when CSM is enabled (doesn't even read the pendrive)...

This is a nightmare.

 

Why not just use the Media Creation Tool to create the Windows 10 USB Flash Drive? Option 1:
USB Flash Drive - Create to Install Windows 10 - Windows 10 Forums

The flash drive created by the Media Creation Tool is good for both Legacy and UEFI installs. The bios setting (Legacy [CSM] or UEFI), the SSD/HDD partition format (MBR for Legacy [CSM] or GPT for UEFI) and the capability of the USB flash drive all have to be the same. The flash drive created with MCT is good for both legacy or UEFI and the install you get from it depends upon which mode the BIOS was set for when the computer boots the flash drive.

 

This is all chinese to me, that is the main problem.

I thought that BIOS had been replaced by UEFI, but I don't really know what they are, I thought that the primary settings of the computer before the OS launches, but after all these new elements called CSM, Legacy, or the way you describe it as if BIOS still was there (I thought it was gone to bring UEFI), etc, is a mess for me and I'd need to search and study a lot of time before understanding it.

Thanks a lot to everybody.

 

Bios is still there and always will be. Legacy bios is the old style booting from MBR type disks. UEFI is a newer type of booting, usually from GPT type disks. CSM is a setting that allows/forces a UEFI bios to boot from MBR type disks- it is legacy booting emulation.

Legacy, UEFI, and CSM are types of booting that the bios performs. Bios will always be required because that is the very basic "mini OS" that controls the functioning of the motherboard before the real operating system loads and takes over. Even then the operating system will use the bios to retrieve information about and interact with the motherboard.

 

A million thanks for the explanation and all your help.

So, if I wipe my disk again and change it to GPT with Partition WIzard and then burn W10 to my pendrive with Media Creation tool, that makes it compatible with MBR & GPT, I will fix the sleep, switch off, fast boot, and all the problems I am having?

That would mean I finally got it... *Biggrin

 

and if your Bios is set for UEFI booting. You would have to enter bios setup to confirm that which is usually pressing DEL repeatedly, (or it could be F2, or whatever the key is for your particular motherboard) when first turning on the computer.

 

Ok thank you very much. I will hav to wait some time before I can wipe the disk again, but I think I got it finally if you didn't disagree with my last post.

THANKS TO ALL.

 

Try Rufus. It works great. UEFI Bootable USB Flash Drive - Create in Windows

You dont need to wipe up the HDD. Follow the Partition Wizard technique to convert it to GPT.

 

And which option should I choose in Rufus?

Thank you very much.

 

This should be OK.

 

Hi, when I try to convert the disk to GPT I get this warning. What should I do? Thanks

 

You have to do it using PW boot CD as stated in post #14 earlier.

 

New problem. After a very slow donwnload of the .iso, apparently I need a tool called Bootable Media Builder to burn it in my USB flash drive, but I can't see where to find it. There is a button for creating a bootable CD on the top right corner of Partition Wizard, but when I click on it, nothing happens. Any idea how I could burn the iso? Thank you very much.

How to build Boot CD/DVD Discs and Boot Flash Drive with Bootable Media Builder?

 

RUFUS, as shown in post #24