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UEFI Boot
hello,
i have dell inspirion 15 3567 and i have formated the old window and installed a new one but i've changed it from uefi boot to legacy boot (boot from cd) . after the download i have tried to change it to uefi boot but after the dell symbole shows up , a memory test appears and after it finishs the computer shut down.
now i have changed to legacy boot and deleted all other boot device except HDD and it works but it take a lot of time to start up . i want to go back to uefi boot with secure boot as it was at thr first time. but it says there isn't a system boot file .
what should i do ????
ejn63
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September 13th, 2017 06:00
In order to run in UEFI mode, Windows must be installed in UEFI mode - you cannot switch modes after installation (except on the Creator's Update version, and even there the utility for doing that isn't entirely reliable).
What version of windows are you running?
jphughan
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September 13th, 2017 12:00
Ejn63 is correct, and fyi you do NOT have to change to Legacy boot just to boot from a CD -- although to boot from a CD in UEFI mode, the environment you're booting from the CD has to actually support UEFI. Windows 8 and above do, so if you switch your PC back to UEFI mode, boot from your Windows installer CD (making sure you choose the CD option under the UEFI boot device category!), you'll be able to install Windows in UEFI mode. You might have to completely un-initialize your hard drive so it's set up for GPT rather than MBR. To do that, after you boot into Windows Setup but before you move forward, press Shift+F10 to open Command Prompt, then enter the commands below. I'm assuming that your system only has one hard drive, but if not, then disk 0 may not be the correct target for this. If you're unsure, after typing "diskpart" below, type "list disk" to see what's available, and then continue as appropriate.
diskpart
select disk 0
clean
After you do that, close Command Prompt and proceed with Windows Setup.
Saltgrass
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September 13th, 2017 12:00
Keep in mind, any UEFI capable install media needs to be available during the initial boot or prior to restart. You can not load it after you have gone into the Bios or some boot device menu.
Raul73
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September 13th, 2017 16:00
i have win 10 pro
also i have to install win 10 one more time over this window in uefi boot . is it true ?
jphughan
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September 13th, 2017 17:00
^ Actually, if you have Windows 10 Creators Update, you can use the included MBR2GPT utility to perform an in-place conversion without needing to perform an entire clean install, which you mentioned in your earlier post in this thread.
OP, basically you would run that MBR2GPT command first (by opening Command Prompt and running "MBR2GPT /convert /allowFullOS"), reboot your system, go into the BIOS before booting again to switch to UEFI mode since Windows won't boot again until you make that change, and then you're set. You may of course want to consider taking a backup first just in case something goes wrong, unless you'd be ok resorting to a clean install if things go badly. I've only used that utility myself once, and initially it threw an error that turned out to be caused by it needing some free space on the disk, so I just had to shrink the last partition on my disk by 1MB (yes, MB) and then run it again, and at that point it worked just fine.
ejn63
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September 13th, 2017 17:00
If you've installed in legacy mode, you will need to do a ground-up reinstall - the disc will be set up as MBR. For UEFI boot, it needs to be set up as GPT.