If you have installed Windows 10 for a long time, for example in a VM or directly on your PC, the old BIOS/MBR boot mode may still be in operation. With the more modern UEFI mode including GPT partition table, your PC may start much faster. In addition, the modern UEFI has some other advantages, such as higher security. And last but not least, the UEFI mode is mandatory if you want to update your Windows 10 to Windows 11. Fortunately, switching from MBR to GPT is possible under Windows 10 without reformatting using on-board tools.
UEFI - what is it?
UEFI, the "Unified Extensible Firmware Interface", the old one has been said for some time BIOS substitute. Of the Disadvantage of the BIOS is that it is a hardware chip, which means that it has certain limitations. And updates aren't easy either. It therefore makes sense to do without this "achievement" that is more than 40 years old.
Check if UEFI or BIOS is active
(U)EFI has been used by Apple since the Intel switch, the implementation under Windows was bumpy for a long time, which means that a whole range of Windows PCs are likely to be on the road that still use the BIOS mode with MBR partition table. The benefit of UEFI with its GPT partition table? Significantly higher speed, better security and easier expandability, in short: everything that PC users need.
And then UEFI is also for the Windows 11 update mandatory requirement. You can check the mode by calling up the system information (msinfo32.exe) under Windows: Under "System Overview" you will see either the entry "UEFI" or "BIOS" next to "Bios Mode". If it says BIOS, you should become active and switch to UEFI – that also works, by the way virtual machines in Parallels or other virtualization solutions!
Optional: Create local administrator
First, when using a live account on Windows, you should make sure you have a local user with admin privileges on hand. Because the login with the live account does not work (at least in our tests). To do this, go to the settings and select “Accounts”.
Click on "Family & other users" and create a local user account with the plus symbol "Add someone else to this PC". You then have to give them administrator rights by clicking on "Change account type" and selecting "Administrator". After confirming with "OK" you have to log in to Windows with this new user.
Start system restore with command prompt
First, make sure that you have backed up all important data on your Windows computer! Then open the "Update & Security" item in the system settings. Click on "Recovery" and then under "Advanced startup" on "Restart now". The computer will now restart with advanced Windows recovery.
In the recovery interface, select the "Troubleshoot" option and then select "Advanced Options" and "Command Prompt".
It will take a while for the next window to appear, but that's OK. Windows will then show you a list of existing users. Select the local administrator and enter the password to start the Windows command prompt.
Convert MBR to GPT and thus BIOS to UEFI
Then only two simple entries are necessary: You must first check whether your PC is suitable for converting from MBR to GPT and thus from BIOS to UEFI. Therefore, type in the command prompt first
mbr2gpt /validate
a. If no error message appears, you can convert your MBR to GPT - and thus use UEFI - with a simple
mbr2gpt /convert
start. The conversion doesn't take too long. You can then close the command prompt and select "Turn off PC".
Turn the PC back on and be happy
Now switch your PC back on: You will probably notice that it starts up much more "smoothly" and faster. In addition, it is now ready for future updates. You can now conveniently check whether everything worked: call msinfo32.exe again and see whether "UEFI" is now under "BIOS mode". You can also take a look at the Disk Management by running diskmgmt.msc: If you click on the Windows disk here at the bottom left and select "Properties", you can see in the "Volumes" tab that your Windows is now working with the GUID partition table (GPT).
I just tried to carry out this procedure on my computer. Unfortunately the action failed with “mbr2gpt /validate”. The error message “validation failed” was a reference to the sector size of 512kB. Are there any special requirements?
I have an SSD hard drive divided into two partitions (NTFS) plus the Windows recovery partition and the system reserved partition.
Additionally, I seem to have a BIOS that apparently automatically detects GPT partitions. I didn't find a dedicated setting option there. However, if I plug in a USB stick with a Linux Live installation, a UEFI boot option is offered for this stick. From this I conclude that a hard drive converted to GPT is actually recognized as such and can be booted via UEFI. Is my assumption correct?
Hallo,
does this guide also work on a 12-year-old PC that has never seen UEFI and there is no option to choose between BIOS and UEFI in the BIOS?
Of course not. You just convert the installation and can then boot it with UEFI. If your computer doesn't have UEFI, it won't start anymore.
Thank you very much for this guide!
The instructions from other sites didn't work.
With this, the transition went smoothly.
< Select the "Troubleshooting" option in the recovery interface and then select "Advanced Options" and "Command Prompt".
This sequence no longer exists. W10 22H2
After troubleshooting comes the Change Startup Settings window, then Reboot - then there is a choice of 10 items - I then chose 6 (Safe Mode - Command Prompt), then Reboot again - Windows Logon - Command Prompt. When entering MBR2GPT Validate - error message "MBR2GPT can only be used from the windows Preinstallation Environment. Use /allowFullOS to overwrite".
Ok, the option must then probably be attached.
So MBR2GPT /validate /allowFullOs
Unfortunately, it was negative for me, although I only have 2 primary partitions and 2 other recovery partitions. Too bad.
Or can I delete the recovery partitions? ….
Thank you for this guide,
until luckily it's not magic.
However, what if validation fails?
After the message <> is of course over for me.
I'm running Win10 21H2 (BIOS start from MBR) in Oracle VM 6.1 for Linux, if I switch to EFI there, I naturally only get as far as SHELL. While I'm not a particularly big Windows fan, family members are. So I should keep this WIN up to date as long as possible.
Is there any possibility that I simply overlooked out of operational blindness or whatever in the vastness of the global data network?
I hope so.
Best regards
Olga
That didn't work... are the comments checked in advance and only then activated?
Worked the first time. Very good guide.
Hello, I did everything exactly as written here and unfortunately my PC won't start up anymore, what now?
Hallo,
OK, of course that's not good. Can you give us some additional information? Basically, it should work as described. You may have to activate the UEFI mode in the BIOS, here is a support article from Microsoft on this: https://docs.microsoft.com/de-de/windows-hardware/manufacture/desktop/boot-to-uefi-mode-or-legacy-bios-mode?view=windows-11
Hello, first of all thanks for the quick reply. Although I'm relatively fit for normal users on the PC, I don't quite understand the article. And since the affected computer no longer boots up, I can only do something in the bios. Since the bios is quite old (was also the reason why I wanted to switch to Uefi) I don't have too many setting options. Can the Uefi mode even be found in an old bios? So when I typed that into the command prompt earlier, I didn't get an error, so I went ahead. However, after the 2 (convert) it only showed me the first 3 lines. Did I maybe close the command prompt too early?
Hmmm...possible. How old is the pc? If he can still use Windows 10, it should actually work and there should be a UEFI switch in the BIOS. That's where you come in, because that's the level in front of the boat.
Be that as it may, does the PC give an error message?
It didn't show an error at all, only after the boot menu it didn't go any further. The PC is about 8 or 9 years old. Windows 10 is not a problem for the computer at all. Loved it too. We just upgraded it with more RAM, bigger FP and different graphics card. After the RAM exchange (was the last thing that was changed, he got stuck in some programs and since the bios is from 0, I thought switching to UEFI would be quite good. I had now set up the computer again and tried it again. This time it had everything displayed as it should be and still didn't start up. Then I wanted to set it up again and this time Windows couldn't be installed because I had the BIOS version of Windows on the stick for the first installation and now the partitions were in GPT. Well Now I've set it up again and will deal with it again in the next few days. First of all, many thanks. I'll get back to you when I find the error. Greetings Nicole
My 13 year old PC runs Windows 10, but I haven't found anything in the legacy BIOS to switch to UEFI. That is probably the prerequisite for the conversion to work. My BIOS: Award Modular BIOS v6.00PG from February 06, 02.
It really did fit right down to the last detail.
For me the best "instruction" so far through the lowlands of the PC.
My Win 11 can come!
Thank you.
A.
Perfect, that's the way it should be! Jnd thank you for the giant coffee :)
Great work!
This should help many Windows users who want to upgrade to Windows 11 and do not understand why "it" should not work according to the Windows message.
I'll see if linking to you on my website (if I may?)
Dirk
Linking is always good :) Glad we could help!