Windows 10: Can't boot in UEFI, only in Legacy, after clean W10 install from USB

Hey folks, i need your help (again)...

I had to reinstall Windows 10 on an Acer Aspire. The "Upgrade Tool" failed repeatedly. I chose to install clean from an ISO to USB using Rufus.

Not knowing the configuration of this laptop, i did a search and found instructions on how to boot from a USB drive, which had me change the CMOS(? F2 at startup) from UEFI to Legacy and use F-12 upon restart to select the USB drive for boot.

Installed Windows 10 successfully.

Boots fine in Legacy mode, but when i change it back to UEFI it gives me a "Boot device not found" or similarly worded error.

Is there an easy fix?

Thank-you! Much appreciate your advice.

:)

 

How to change a legacy Boot W10 diskt to use UEFI Boot

Hi all,

I would like to modernize my well running W10 by changing the boot process to UEFI (Reason: Using NVmE SSDs or GPT sized disk). Because the system has many well configured apps used day by day a clean install would be the least favorable choice.

So my questions are:

• Is it possible to patch a fully installed and featured W10 from legacy boot to UEFI boot? And how?
• If possible: does a patched system needs a new activation (Its a migrated W10 from W7)?

BTW: I have already read lots of post dealing with UEFI. But I didn't find any usable answer yet.

TIA and best regards.

 

UEFI vs Legacy boot mode

I recommend you stick with legacy install instead to avoid any compatibility problem hardware or software. Uefi have the speed advantage for boot up but I don't find it to be a good trade-off for the compatibility problems that appeared. Secure boot for uefi is a pain if you decide to install multiple os as the other os is "locked" out. I used uefi for my previous install it is a lengthy install selecting the correct bios setting without borking the install. I'll move to uefi if I don't have a need for multiple os or legacy things. So far I seem to need it.

 

Notebook boots in Legacy not UEFI

Hi HannanShaikh,

You can convert your Legacy mode drive to UEFI boot anytime, visit this link:
Windows Setup: Installing using the MBR or GPT partition style for a comprehensive guide to reformat your hard disk to boot it to a UEFI mode.

The option to "Boot the PC to the DVD or USB key in UEFI mode" is also provided there.

Make sure that you use the same USB drive which already matched the edition of Windows 10 for your computer.

If you continue to have this issue even after performing the above steps, please reply to this thread. The system will notify me so I can get back to you and provide you more answers.