Fix Error 0X0000091D: Device Not Open on Windows

You get error 0X0000091D, and nothing works. The device just won't open. Annoying as hell, but the fix is usually simple. Let's get to it.

First Fix: Full Shutdown (Not Restart)

This is the one that works 90% of the time. Windows 10 and 11 have a feature called Fast Startup. It saves some system state to disk so booting is faster. But it also keeps device handles locked across reboots. A normal restart doesn't clear those handles. You need a full shutdown.

1. Click the Start button, then the Power icon.
2. Hold down the Shift key on your keyboard.
3. While holding Shift, click Shut down. Keep holding Shift until the screen goes completely black.
4. Wait 30 seconds. Then press the power button to boot normally.

What's actually happening here is that holding Shift bypasses Fast Startup. Windows performs a full kernel shutdown. That releases any broken locks on the device. When you boot again, the driver reinitializes properly.

Try your device again. If the error is gone, you're done.

Second Fix: Device Manager Reset

If the full shutdown didn't work, the driver itself might be stuck in a bad state. Don't reinstall it yet. First, reset the device in Device Manager.

1. Right-click the Start button and select Device Manager.
2. Find your device — it's usually under Universal Serial Bus controllers for USB devices, or under Printers, Imaging devices, or Other devices with a yellow triangle.
3. Right-click the device and choose Disable device. Confirm the warning.
4. Wait 10 seconds. Then right-click again and choose Enable device.

The reason step 3 works is that disabling the device forces the driver to unload from memory. When you re-enable it, Windows reloads the driver fresh. This clears any internal error state. No restart needed.

Why This Error Happens

Error 0X0000091D comes from the Windows kernel. It means a device driver tried to open a hardware device, but the device was already open by another process. This usually happens after:

• A program crashes while using the device (like a scanner app that hangs).
• You unplug a USB device without safely removing it first.
• A driver update fails halfway through.

The device handle — think of it as a permission slip — doesn't get released. The next time anything tries to use the device, Windows says "No, it's already in use." Even if the original process is dead.

Less Common Variations

Sometimes the same error shows up with different numbers. You might see 0x80070241, 0x0000009D, or just "This device was not open." They all mean the same thing: a locked handle. The fix is identical.

If you're on an older Windows version (7 or 8.1), the Shift+Shutdown trick might not work. In that case, disable Fast Startup in Power Options:

1. Go to Control Panel > Power Options > Choose what the power buttons do.
2. Click Change settings that are currently unavailable.
3. Uncheck Turn on fast startup.
4. Click Save changes and restart.

After that, a normal shut down will perform a full shutdown every time.

When to Reinstall the Driver

If neither fix works, the driver files might be corrupted. Don't do this as a first step — it's overkill. But if you're still stuck:

1. Open Device Manager.
2. Right-click the device and choose Uninstall device.
3. Check the box Delete the driver software for this device.
4. Restart your PC normally. Windows will reinstall the driver automatically.

This wipes the driver completely. Windows grabs a fresh copy from its cache or Windows Update. Much cleaner than a manual download.

Prevention

To stop this error from coming back, three habits help:

• Always use "Safely Remove Hardware" before unplugging USB drives or printers. It tells Windows to release the handle cleanly.
• Don't force-close applications that use hardware — like scanning software. Let them close normally.
• Keep Windows updated. Microsoft fixed many related bugs in Windows 10 20H2 and later.

If you use a printer or scanner daily, set it to stay connected even when idle. Some devices go to sleep and wake up with a new handle, which can cause conflicts over time.

Error 0X0000091D is almost never a hardware failure. It's a software lock that got stuck. A full shutdown is usually all you need.