Windows Boot Repair Tool

Before you begin: If the drive is not visible in BIOS/UEFI, or CHKDSK reports bad sectors, prioritize backing up important data and checking the drive or its connections.

1Identify the boot symptom

Choose the message or behavior that best matches what you see after powering on.

What do you see?

No bootable device / Insert boot media BOOTMGR is missing / Operating system not found Preparing Automatic Repair loop Blue screen while booting Windows logo or spinning dots never finish Something else / not sure

2Check the drive and boot order

Enter BIOS/UEFI setup and make sure the Windows drive is detected and selected as the correct boot device.

Is the Windows system drive detected?

Yes, it is listed No, it is not listed Not sure

Is the boot order correct?

Yes, Windows Boot Manager or the system drive is first No, USB, network, or another drive is first Not sure

3Verify boot mode compatibility

Windows must boot in the same mode in which it was installed: UEFI with GPT, or Legacy/CSM with MBR.

Current firmware boot mode

UEFI Legacy / CSM Mixed / both enabled Not sure

Windows installation type, if known

GPT + UEFI MBR + Legacy Not sure

4Run Startup Repair in Windows Recovery

From Windows Recovery, select Troubleshoot → Advanced options → Startup Repair. If recovery will not load, start from a Windows installation USB and select Repair your computer.

Startup Repair result

It fixed the problem and Windows boots It found no issue, but Windows still will not boot It could not repair the PC I have not run it

5Repair boot files from Recovery Command Prompt

For many Legacy/MBR installations, these commands can rebuild startup records. Use them only in the Recovery Command Prompt.

bootrec /fixmbrbootrec /fixbootbootrec /scanosbootrec /rebuildbcd

UEFI/GPT systems commonly need an EFI partition repair with bcdboot rather than only the commands above. Confirm your boot mode before making changes.

What was the result?

The system now boots The error changed or there was partial improvement Commands failed or made no difference I did not run them

6Check disk and offline system files

File-system damage and missing Windows files can prevent startup. Run checks from Recovery Command Prompt, using the correct Windows drive letter.

chkdsk C: /f /r sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows

CHKDSK result

No errors found Errors were found and repaired Serious errors or bad sectors were reported Not run

Offline SFC result

It repaired files It could not repair everything or failed Not run

7Review recent changes and current status

Recent disk changes, cloning, partition work, or dual-boot setups can alter the boot configuration.

Was there a recent change?

Added, removed, cloned, or replaced a drive Resized or moved partitions Multiple operating systems / Linux dual boot No major recent change

Current boot status

Windows now boots normally It boots only sometimes It still does not boot

Summary & Suggested Next Steps