Windows 10: Legacy Boot is greyed out in BIOS

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UEFI and Legacy are the two modes of BIOS. The UEFI mode of BIOS has several advantages over the Legacy BIOS mode. That’s why the Legacy BIOS mode has become less popular after the introduction of UEFI. Some of the advantages of UEFI include a faster booting process, support for the hard drives larger than 2 […]

This article Legacy Boot is greyed out in BIOS first appeared on TheWindowsClub.com.

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Difficulty setting BIOS to boot in Legacy mode

Hi,

I read that from your previous link...

That's why I was thinking that a wiped HDD might give a different outcome with the BIOS...

Same reason to try doing a Clean Install with a Flash Drive specifically for Legacy Bios... To see if the Legacy\ Secure Boot issue can be forced to change...

Be sure to have all other HDDs and iOmega stuff unhooked...

I am trying to force something to work on my machine by using a UEFI Flash, as opposed to the Legacy Flash I suggested you try...

I'm trying to boot off of a PCIe based SSD, and my Bios is not recognizing it in Legacy... Not even showing in Bios at all, even though it works fine for Data storage...

 

Legacy BIOS Boot Support Removal for Intel Platform

This, from Lenovo....

Legacy BIOS Boot Support Removed in Lenovo 2020 products - Lenovo Support US

 

Difficulty setting BIOS to boot in Legacy mode

Hi,

It is possible that Win 8 didn't have that EFI partition, but it probably did...

If it did not, and you upgraded to Win 10, it would not have been added...

A clean install is a different animal, especially if your machine was set for UEFI when you did it... If you could set the machine to legacy for instance, it is doubtful that the EFI partition would be there...

Btw... if you get the chance, look to see if your BIOS has a setting concerning "CSM" or similar... It would probably be in the same area where you select Legacy...

Here is a note I found concerning that setting...

Quote...

The UEFI boot manager is able to load legacy BIOS environment using the Compatibility Support Module (CSM). This module is able to emulate
legacy BIOS environment and allow booting legacy operating systems or new operating systems which were installed without UEFI boot loader