Windows 10: Cannot switch to UEFI from Legacy boot

I have an Acer Aspire E5-575G and was using the new PC Health Check application by Microsoft which has the new option to check if my computer is compatible for Windows 11. It's not, and it mentions the problem is that Secure Boot is not enabled.When I try to switch in BIOS from Legacy to UEFI mode, I get the Secure Boot option and have it enabled. Although when I now launch, I get: "No Bootable Device".Please let me know how I can fix this, thanks!

:)

 

Need to convert Windows 8.1 from UEFI boot to legacy boot

I have switched the boot mode from UEFI to Legacy. Is there a way to change the existing Windows 8.1 to boot in Legacy mode, or do I need to reinstall Windows?

(I dual-boot Windows and Linux on all my PC's. I have a Toshiba Sattelite that refuses to boot Linux in UEFI mode (tried Debian, Fedora, Suse, and Arch, with various workarounds, secure boot is disabled). As a last resort I switched to Legacy boot mode.
Linux boots fine in Legacy mode, but now Windows will not boot.)

 

UEFI or Legacy?

So i went for a clean Windows 10 installation on my Aspire E13.
To boot from USB i had to switch from UEFI to Legacy, otherwise the USB drive would not be listed.

However. After the installation was finished my touchpad was not even recognized, i mean, i was not even listed in the device manager, so i read somewhere on the Acer forum that switching back to UEFI would solve this problem.
Well, i switched back to UEFI and now when the laptop start i recieve a message that says -No bootable device found!

Even if i try to use my bootable USB drive, the list is empty.
So i switched back to Legace again and guess what. Windows 10 starts like there was no problem.

So, what's the different between UEFI and Legacy? The bios tells me -Use UEFI on Win 8 and above to use all the benefits.
And why oh why can't i boot up from a existing and working Windows 10 drive using UEFI?

 

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.