I tried to prepare my PC for a game that requires TPM 2.0 and Secure Boot. I changed several BIOS settings, including disabling CSM and enabling Secure Boot, and then ran `mbr2gpt /validate /allowFullOS`, which completed successfully. After running `mbr2gpt /convert /allowFullOS` and restarting, the computer began repeatedly rebooting and never reaches Windows. I reset the BIOS settings, disabled Secure Boot, and re-enabled CSM, but the boot loop continues. I'm not very experienced with computers and have important files on the drive, so I need to know how to recover Windows without losing my data.
3 Answers
Your PC probably isn’t permanently bricked. The command converted the Windows drive from MBR to GPT, so Windows now needs to boot in UEFI mode rather than legacy/CSM mode. Enter BIOS and set the boot mode to UEFI, disable CSM or Legacy Boot, and make sure Windows Boot Manager for the correct drive is the first boot option. Don’t run a reinstall or format the drive yet.
Your files may still be intact; a boot loop does not automatically mean the data is gone. If the files are important, stop experimenting and connect the drive to another computer or take the PC to a reputable repair shop so the data can be copied before attempting more repairs. Reinstalling Windows should be a last resort, and you should back up important files once the system is accessible again.
Try to recover the exact AI instructions and write down every BIOS change that was made. You can also clear the CMOS to reset firmware settings, then configure the system for UEFI boot and check whether Windows Boot Manager appears. If it does not, use a Windows installation or recovery USB to enter Startup Repair or the command prompt and repair the boot files. Avoid repeated changes until you know whether the drive is being detected.
Before the conversion, setting BIOS defaults let Windows start normally. After running the conversion, it began looping, even after I changed the BIOS settings back.