Problem with PC not starting in UEFI setup.
Problem with PC not starting in UEFI setup.
PC Specifications: CPU upgraded to Ryzen 5 5600X, Motherboard MSI X470 Gaming Plus, RAM Kingston DDR4 16GB at 3200MHz, GPU RTX 2060 6GB. I recently replaced my CPU and RAM from a Ryzen 5 2600 16GB to the new model. Before installing the new parts, I updated the BIOS to the latest non-beta version using the 2600. I encountered issues booting into Windows 10 via UEFI, so I changed the BIOS setting to CSM mode, which resolved the problem and allowed a successful boot. How can I configure my PC to use UEFI mode? Are there any disadvantages to operating in CSM mode?
Based on my understanding of UEFI setup, this process usually involves updating the UEFI Boot Partition after flashing the BIOS. Often it favors Windows 10, but sometimes the partition is damaged. If you execute these commands while the system is disabled (via the installation media, Troubleshoot > Advanced Options), we should be able to restore your Windows quickly using the provided tools.
When you start from the Windows 10 installation media, usually a USB drive, you’ll notice a message that says "Repair your computer."
Please hold on while it transfers to your USB drive. If the problem persists, a full Windows reinstall might resolve the issue.
A full system reset would be effective since it updates the UEFI Boot section during setup. Still, replacing the OS is very damaging—it requires installing every app and could erase all your files.
I attempted the steps you mentioned, using the Windows 10 USB setup and executing the commands. The bootrec /fixboot failed. After that, when I tried bootrec /rebuildbcd, it prompted me to add the installation to the boot list—yes—and it told me the system device couldn’t be located. The PC is now blocking boot entirely with the UEFI.
They switched CSM into operation, but prior to the upgrade it wasn’t required. The motherboard and operating system both allow UEFI, so CSM was merely a temporary solution for the real issue
You're right, you don't need a full reinstall to switch from CSM to UEFI. This is often the case when working with older Windows versions that were likely created in legacy mode.