My sons PC MSI Z390 Gaming edge AC I have checked his bios and it is set to csm when i change it to uefi to setup tpm and secure boot it boots back to bios, he wants it ready for windows 11. Will i need to format and re install or are there other options.
Os needs to be installed on gpt disk while csm disabled to boot in uefi. So yes, format is needed. You can check in windows if system is running in legacy or uefi mode.
Windows can be installed in UEFI mode with CSM enabled in BIOS. But you have to install Windows by booting from UEFI installation disk (USB or optical).
To OP, I just did this to two PC's running two different Asrock's Z390 MoBo's running NVME in MBR this weekend. There are a few ways of doing it. You can do this without formatting your current OS drive, and keeping drive intact. Go read this page ( https://www.easeus.com/partition-ma...gpt-to-mbr-using-cmd-without-losing-data.html ) on the different ways to it. I followed tip #4 using command prompt within advance start up, and it work great. But, I highly recommend having a backup of the OS drive just in case, not just for this, but for any situation. Convert MBR to GPT Without Losing Data with MBR2GPT MBR2GPT.exe is a Windows built-in tool used to convert the disk from MBR to GPT. The advantage of this tool is that it won't destroy the files on your disk during the conversion. It is only available in Windows 10 version 1730 and later. Run MBR2GPT in WinPE to Convert MBR to GPT CMD Step 1. Click the Start button > click the Power button > hold the Shift Key and click Restart to access the Advanced Startup screen. Step 2. Navigate to "Troubleshoot > Advanced options > Command Prompt". Step 3. In Command Prompt, input these commands orderly, and press Enter after each command line. mbr2gpt /validate mbr2gpt /convert
Yeah, I found it not complicated. I just copied and pasted that whole post from the web site I linked. But, I could see some people who never used command prompt a little nervous.
