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+--- Thread: MBR vs GPT - Secure Boot (/showthread.php?tid=4240)
MBR vs GPT - Secure Boot - Galaxy01 - 08-08-2025
Good morning, folks.
1. If my current Windows is MBR and needs to turn ON Secure Boot which will be changed to UEFI (GPT); by doing so, can I still load Windows?
2. Bootable USB must be using MBR?
RE: MBR vs GPT - Secure Boot - Wainuitech - 08-08-2025
Do you mean will the existing Install Load or is it a fresh install ??
Generally if you go into the boot menu it may show two options to boot from the USB, 1 being UEFI, the other just the USB ( try both)
RE: MBR vs GPT - Secure Boot - king1 - 08-08-2025
I haven't come across a tool that can convert a MBR drive to GPT without destroying the user data.
So from that POV no. it won't then load windows.
If anyone knows of one I would like to know...
RE: MBR vs GPT - Secure Boot - Wainuitech - 08-08-2025
(08-08-2025, 03:00 PM)You Can convert, its a command Prompt from memory -I'll loook up the king1 Wrote: I haven't come across a tool that can convert a MBR drive to GPT without destroying the user data.
So from that POV no. it won't then load windows.
If anyone knows of one I would like to know...
You can convert the system from MBR to GPT. ( done it a couple of times) From Memory its a command you enter ( inbuilt in Windows) I'll look it up and post the details later tonight as soon as I find it.
EDITED: FOUND IT
For once I wrote it down. IMPORTANT -- Make sure you image the whole system 1st in case it fails.4. Convert MBR to GPT:
If you're using an older MBR (Master Boot Record) partition style, you'll need to convert it to GPT (GUID Partition Table) to fully support UEFI and Secure Boot.
You can use the mbr2gpt tool (built into Windows) to convert the drive without data loss.
Important: Back up your data before using mbr2gpt or any other disk conversion tool.
Using MBR2GPT (Recommended):
1. Open Command Prompt as Administrator:
Search for "cmd" in the Start Menu, right-click on "Command Prompt," and select "Run as administrator."
2. Validate the conversion:
Type mbr2gpt /validate and press Enter. This will check if the disk can be converted without issues.
3. Convert the disk:
If validation is successful, type mbr2gpt /convert and press Enter. This will initiate the conversion process.
RE: MBR vs GPT - Secure Boot - king1 - 08-08-2025
hmm so I am aware of that one but for some reason came to the conclusion that it wouldn't work when i tried it awhile back. Might need to have another play around with that one...
RE: MBR vs GPT - Secure Boot - Wainuitech - 08-08-2025
(08-08-2025, 03:49 PM)king1 Wrote: hmm so I am aware of that one but for some reason came to the conclusion that it wouldn't work when i tried it awhile back. Might need to have another play around with that one...
Sometimes it Doesn't, I know once it wouldn't (can't remember why now) failed the validation.
But an interesting article describes how A ConfigMgr Geek’s Guide to the MBR2GPT.exe Tool
Old story, always make an image /backup 1st, just in case.
The last one I did was a Windows 10 with several original configuration changes needed to upgrade to W11. The CPU was fine, but needed TPM enabled, MBR to GPT, and secure boot enabled. Didn't really want to reinstall as the person had a couple of programs they used daily, that no longer could be downloaded or obtained.