Error codes

0xc0000185

I/O error on the boot device

What it means

The boot loader found the drive but could not read the data it needs, so Windows never started.

Common causes

• A damaged partition table or boot sector
• A failing drive
• A SATA mode change in the BIOS (AHCI to RAID)

How to fix it

1. Set the SATA mode in the BIOS back to what it was when Windows was installed (usually AHCI).
2. Boot from a Windows USB stick and run Startup Repair.
3. Run chkdsk C: /r and check the drive's SMART values.
4. Back up what you can before any repair that writes to the disk.