Although moving from Legacy to UEFI BIOS on Windows 10 is very easy, there are some factors to consider before:
- By thought there will be no data loss in the middle of the process, unless something goes wrong and goes wrong. In any case, it is best to make a backup of data when possible.
- You need an version 1703 for Windows 10 at least
- The disk you are trying to convert you must not have more than three divisions.
- If you are using Bitlocker to encrypt a hard drive, you must uninstall it and then disable the bitlocker for the conversion to take effect.
- Once the modification is done, it may be necessary Install BIOS to switch from Legacy BIOS to UEFI
Check that you are using Legacy BIOS and not UEFI
The previous step before moving from one to the other is, of course, make sure you are not using UEFI mode at all. To test it, access Windows 10 disk manager (right-click the Start button and select «Disk Management«. Locate the main program disk in the area below, click on it and select «Properties».
In the popup window, go to the Volume tab, and in "Partition style" we should check if it's Master Boot Record (MBR), that's where we have Legacy BIOS and if we can make the change, or if not. It says "It's a GUID partition table (GPT)", then we'll be using the UEFI BIOS (as an example).
Convert Legacy BIOS to UEFI
Once we have confirmed that we are using Legacy BIOS and have done all the previous steps, we need access to the advanced Windows boot options. To do this, you must click on the first icon, select "Calm down" or log out again click "Restart" but while holding down the SHIFT key
For starters, we should go to the "Troubleshoot" and "Advanced Options" menu. When we get there, we select the Command Prompt (or command command).
A black command prompt window will open. The first thing we need to do is verify the disk we want to use for conversion, and for this we have to write the following command and press ENTER:
mbr2gpt / authentication
If we see the message "Authentication successfully completed" or "Authentication successfully completed", then we can move on to the next step. If an error message appears here, then we do not meet the requirements we originally set.
After verifying the disk, to continue the conversion we must issue the following command:
mbr2gpt / convert
As soon as we run it, the conversion process will start, which can take from a few seconds to a few minutes depending on our hardware and configuration.
When we are done, we can restart the program and the best is access the BIOS directly to switch from Heritage to UEFI. How to do this depends on the boards of each board so we recommend that you carry it manually.
Once we are done we can start Windows 10 normally, and if we repeat the previous step to check if we have Legacy or UEFI, we already see that we are in GPT mode, which is UEFI.