I recently ran mbr2gpt.exe to convert my hard drive to GPT. After that, I changed my BIOS settings to UEFI and enabled Secure Boot. Now, my PC won't boot into Windows at all. Even switching the boot mode back to CSM hasn't fixed the issue. Any advice on how to resolve this would be greatly appreciated!
1 Answer
First, try disabling Secure Boot and then switch UEFI back on. Make sure your BIOS actually detects the boot loader—there should be an entry for it. If that doesn't work, you might need to create a Windows USB installer and boot from it in UEFI mode. When you're in the recovery menu, open up a command prompt and follow these steps:
1. Type `diskpart`
2. Then use `list disk` to see your drives.
3. Select your system disk with `select disk 0` (or whichever one is correct for you).
4. Next, type `list partition` to see all partitions.
5. Select your EFI partition using `select partition X` (your EFI partition is usually around 100MB and FAT32).
6. Assign a letter with `assign letter=S`
7. Finally, run `bcdboot C:Windows /s S: /f UEFI` to fix the boot loader.
After that, reboot without the USB stick and check if it works!
I did something similar, and my SSDs didn’t show up either with UEFI. They only appeared when I switched back to CSM. It felt like something went wrong during the conversion.