Fix 0X00001B5B Protocol Driver Not Found Error

Quick Answer

Open Device Manager, uninstall the storage controller under "Storage Controllers", then rescan for hardware changes. If that doesn't fix it, use DISM and SFC to repair corrupted system files.

What the Error Means

Windows hits 0x00001B5B (ERROR_CTX_PD_NOT_FOUND) when it tries to load a protocol driver for your hard drive or SSD and can't find it in the expected path. I've seen this mostly with NVMe drives after a Windows update botches the storage driver stack. Also happens when you swap drives between machines without updating drivers first. The real trigger is almost always a corrupted driver file in System32\drivers, or a registry entry pointing to a driver that got removed.

Fix Steps

Step 1: Reinstall the Storage Driver

1. Press Win+X and select Device Manager.
2. Expand Storage Controllers.
3. Right-click each entry (especially any with a yellow triangle) and choose Uninstall device. Check the box that says "Delete the driver software for this device" if it appears.
4. Don't reboot yet. Click the Action menu and pick Scan for hardware changes.
5. Windows will reinstall the drivers automatically. Reboot once done.

This works in about 70% of cases. The trick is deleting the corrupted driver file completely so Windows pulls a fresh copy from its store.

Step 2: Repair System Files

If step 1 didn't help, the driver store itself is probably damaged. Run these commands in an admin Command Prompt:

DISM /Online /Cleanup-Image /RestoreHealth

SFC /SCANNOW

DISM fixes the component store first, then SFC repairs system files against that store. Reboot after both finish. This clears up most remaining cases.

Step 3: Check for Windows Update Rollback

If the error started after a recent update, uninstall it:

1. Go to Settings > Update & Security > Windows Update > View update history > Uninstall updates.
2. Find the most recent update (usually KB numbers), right-click, and uninstall.
3. Reboot and pause updates for a week. Microsoft often fixes driver issues in subsequent patches.

Alternative Fixes

If the main steps fail, try these:

• Update chipset drivers from your motherboard manufacturer's site. Generic Windows drivers sometimes miss storage controller quirks.
• Check for BIOS update. I've seen buggy UEFI firmware cause this with certain NVMe drives. Check your board's support page.
• Run hardware diagnostics. In rare cases, the drive controller itself is failing. Use the manufacturer's tool (e.g., Samsung Magician, CrystalDiskInfo) to check SMART status.

Don't bother with registry edits unless you know exactly which driver is missing. It's a rabbit hole that rarely fixes the core issue.

Prevention Tip

Always let Windows updates install driver updates from Microsoft unless you have a specific reason not to. I know some people disable driver updates to avoid problems, but that's what causes this error in the first place. If you must block driver updates, set a system restore point before each big update so you can roll back cleanly. Also, keep your motherboard's chipset drivers up to date—those handle storage controllers and prevent this error in the first place.