Windows 10: Boot issue after a clean installation of WIN10 on older computers with 'Legacy' BIOS-mode.

I have a tip that might help people having issues with a clean installation of WIN10 on older computers. I did a clean install of WIN10 on a HP Probook 4740s tablet because it was becomming extremely slow. Everything went well until I rebooted the machine. It didn't start up anymore. I had no clue what caused this so I contacted HP. Changing the BIOS 'Legacy' setting into 'UEFI' solved the issue. For one reason or another WIN10 has to be booted in 'UEFI'-mode.

:)

 

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...

 

Difficulty setting BIOS to boot in Legacy mode

I tried all that is suggested by HP but it makes no difference, the Legacy mode simply refuses to stay put. I always ensure that the settings are confirmed before exiting the Setup but that's just it ... the machine always goes back to Secure Mode. Annoyingly,
prior to the iOmega software being installed and the consequential failure to boot, I could set the PC to boot into Legacy mode with no problem if I chose to.

 

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