What is INACCESSIBLE-BOOT-DEVICE?
INACCESSIBLE_BOOT_DEVICE is a critical-severity storage drive (SSD/HDD) problem. Windows cannot access the system disk at startup. Common triggers are changing SATA mode in BIOS and corrupt MBR/GPT. Use the steps below to track down and fix the cause.
Common Causes
- Defective disk
- Changing SATA mode in BIOS
- Corrupt MBR/GPT
Step-by-Step Fix Guide
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1
Check SATA/NVMe mode (AHCI vs RAID)
Begin with Check SATA/NVMe mode (AHCI vs RAID); it's the step that resolves INACCESSIBLE_BOOT_DEVICE for the largest share of reported cases.
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2
bootrec /fixboot
Should the issue continue afterward, the remaining steps are there to cover the less common storage instability scenarios.
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3
Startup Repair from USB
Try "Startup Repair from USB" next if the issue persists — it addresses a secondary cause.
Commands & Diagnostics
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
Frequently Asked Questions
INACCESSIBLE-BOOT-DEVICE is most often triggered by defective disk. Other reports point to changing SATA mode in BIOS and corrupt MBR/GPT as contributing factors.
Try "Check SATA/NVMe mode (AHCI vs RAID)" first — it resolves most INACCESSIBLE-BOOT-DEVICE cases on its own. Only work through the rest of the guide above if it comes back.
Treat INACCESSIBLE-BOOT-DEVICE as urgent — it's flagged critical severity, meaning repeated occurrences risk data loss or hardware damage.
In most cases, yes — the guide above resolves INACCESSIBLE-BOOT-DEVICE without a clean install. Treat a reinstall as the last resort, not the first move.
Open CrystalDiskInfo (free tool) to check your drive's S.M.A.R.T. status. Any yellow or red indicators — especially reallocated sectors or pending sectors — confirm the drive is degrading and should be backed up and replaced immediately.
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