Tech Guide

Windows Device Manager Error Code 51: A Practical Troubleshooting Guide

Learn what Windows Device Manager Error Code 51 means and follow practical steps to troubleshoot the device, drivers, dependencies, and related hardware.

By Dan Huskey•Published Nov 9, 2026•Updated Nov 10, 2026

If Windows Device Manager shows Code 51, the device you’re looking at may not actually be the device causing the problem.

Code 51 means Windows is waiting for another device, or set of devices, to start before it can start the affected device. That makes troubleshooting Code 51 different from a typical missing-driver problem.

Instead of repeatedly reinstalling the driver for the device showing the warning, the key is to determine what that device is waiting for.

This guide walks through that process step by step.

What Does Device Manager Code 51 Mean?

The full Device Manager message is:

This device is currently waiting on another device or set of devices to start. (Code 51)

Microsoft identifies Code 51 internally as:

CM_PROB_WAITING_ON_DEPENDENCY

In practical terms, Windows knows about the device and its driver, but another component the device depends on has not successfully started.

That dependency could involve another hardware device, a controller, a chipset component, firmware, or another part of the device’s driver stack.

This distinction matters.

If Device Manager says a camera has Code 51, for example, replacing the camera driver over and over may accomplish nothing if the camera is actually waiting for a related controller to start.

Before You Start

Before changing drivers or firmware, do a few basic things first.

Create a restore point or backup

Driver, chipset, and firmware troubleshooting can affect multiple devices.

At minimum, make sure important files are backed up before making substantial changes.

Record the current configuration

Before uninstalling anything, take screenshots of:

The device showing Code 51
The Device status message
Any listed dependencies
The Driver tab
Driver provider
Driver date
Driver version

This gives you a reference if the troubleshooting process changes the driver configuration.

Know your computer model

If you’re troubleshooting a prebuilt PC or laptop, identify its exact model before downloading drivers.

Use drivers intended for your specific computer whenever possible, particularly for:

Chipset components
Cameras
Thunderbolt or USB4 controllers
Serial IO devices
Intel MIPI components
Firmware
BIOS/UEFI

A driver being newer does not automatically mean it is the correct driver for your system.

Step 1: Restart Windows

Start with a real restart.

Go to:

Start > Power > Restart

Don’t just close the lid or put the computer to sleep.

Code 51 involves a device-start dependency, so restarting Windows gives Plug and Play another opportunity to initialize the hardware stack in the correct order.

After Windows restarts:

Open Device Manager.
Locate the affected device.
Right-click it and select Properties.
Check Device status.

If Code 51 is gone, test the device itself before doing anything else.

If Code 51 returns, continue.

Step 2: Look at the Dependencies Listed With Code 51

This is one of the most useful clues in the entire troubleshooting process.

Open:

Device Manager > affected device > Properties

Read the complete message under Device status.

Depending on the device and driver, Windows may list one or more dependencies underneath the Code 51 message.

They may look unfamiliar. You might see identifiers associated with:

ACPI devices
PCI Express devices
USB controllers
Intel platform components
Camera controllers
Serial IO devices
Thunderbolt or USB4 components

Don’t worry if the names aren’t immediately understandable.

Record them exactly.

The goal is to answer:

What other device is this device waiting for?

That’s usually more useful than asking why the Code 51 device itself won’t start.

Step 3: Look for Other Problem Devices

Next, inspect Device Manager as a whole.

Look for devices displaying a yellow warning icon, especially under:

Cameras
System devices
Software components
Universal Serial Bus controllers
USB Connector Managers
Human Interface Devices
Sensors
Imaging devices
Other devices

Check the properties of each warning device.

You are looking for another error that may explain why the Code 51 device is waiting.

For example, you might discover that the visible device has Code 51 while a related controller has:

Code 10
Code 28
Code 31
Code 43
Code 48
Another device-start error

In that situation, concentrate your troubleshooting on the device that failed earlier in the dependency chain.

A computer can have multiple unrelated Device Manager warnings.

Use the dependencies listed with Code 51, device names, hardware IDs, and the system’s hardware architecture to determine which devices are likely connected.

Step 4: Use PnPUtil to Find Problem Devices

For a more complete view, Windows includes the PnPUtil command-line utility.

Open Terminal as Administrator and run:

pnputil /enum-devices /problem

Step 5: Check Windows Update

Next, check whether Windows has driver or firmware updates available.

Go to: Settings > Windows Update

Install applicable Windows updates and restart if required.

Then check: Windows Update > Advanced options > Optional updates

If Windows offers relevant hardware drivers, review them carefully.

After installation, restart Windows and check Device Manager again.

Don’t blindly install every optional driver

If your PC manufacturer supplies a specific driver stack for the affected hardware, I generally prefer the manufacturer’s tested package for tightly integrated devices such as:

Laptop cameras
Chipset components
Thunderbolt controllers
Serial IO devices
Sensors
Platform firmware

This is especially important on newer laptops where one physical feature may depend on several drivers and firmware components working together.

Step 6: Check the Computer Manufacturer’s Drivers

Go to the support site for your exact computer or motherboard model.

Look for relevant updates in categories such as:

Chipset
Camera
Serial IO
Thunderbolt or USB4
Sensors
Graphics
System firmware
BIOS/UEFI

For an integrated laptop camera, for example, the camera may be only one piece of a larger imaging stack.

A modern camera implementation can involve several supporting devices and drivers. If one controller fails to initialize, Device Manager may report Code 51 against another component farther up the chain.

Install platform dependencies before repeatedly reinstalling the end device

If the computer manufacturer provides several related packages, pay attention to the relationship between them.

A reasonable troubleshooting order is:

Chipset and platform components
Controller or Serial IO packages
Related firmware
Device-specific drivers
Restart Windows
Recheck Device Manager

If the manufacturer’s documentation specifies a particular installation order, follow that instead.

Step 7: Check BIOS and Firmware Updates

Code 51 isn’t necessarily limited to a Windows driver problem.

Check the computer manufacturer’s support site for:

BIOS/UEFI updates
Device firmware updates
Embedded controller updates
Thunderbolt or USB4 firmware
Camera firmware
Other model-specific platform updates

Read the release notes before installing an update.

Firmware updates should not be interrupted. A laptop should be connected to AC power during BIOS or firmware updates.

After an update:

Allow the computer to restart normally.
Sign in to Windows.
Give Windows time to enumerate the hardware.
Open Device Manager.
Check the affected device and related devices again.

Step 8: Reinstall the Affected Device Carefully

If the dependency chain appears healthy but Code 51 remains, reinstalling the affected device is reasonable.

In Device Manager:

Right-click the affected device.
Select Uninstall device.
Review any additional options Windows displays.
Click Uninstall.
Restart Windows.

Windows may redetect the hardware automatically.

You can also use:

Device Manager > Action > Scan for hardware changes

After Windows reinstalls the device, open its properties and check Device status again.

Be careful when deleting driver packages

Removing a device and deleting its driver package are not the same thing.

For integrated laptop hardware, I prefer having the correct manufacturer-provided driver package available before deliberately removing an existing package from the Windows Driver Store.

That gives you a known-good recovery path if Windows cannot automatically reinstall the correct driver.

Step 9: Check Whether Windows Security Is Blocking a Driver

Windows security features can prevent incompatible or vulnerable drivers from loading.

If Windows specifically reports that a driver cannot load, check:

Windows Security > Device security > Core isolation > Core isolation details

Microsoft documents that Memory Integrity can prevent incompatible drivers from loading. Microsoft’s preferred first step is to look for an updated compatible driver through Windows Update or the device manufacturer. 【1-65cbad】

I would not disable Memory Integrity as an early troubleshooting step.

Turning it off reduces an important Windows security protection. Microsoft specifically warns that disabling Memory Integrity on a Secured-core PC takes the device out of its Secured-core state. 【1-65cbad】

If an old driver works only after disabling a security feature, look for a corrected driver or firmware package before accepting that as a permanent solution.

Step 10: Recheck the Entire Dependency Chain

Now return to Device Manager and inspect the system again.

Don’t look only at the original Code 51 device.

Ask:

Did another warning disappear?
Did any new device appear?
Did another device change from one error code to another?
Are the related controllers now starting?
Has the dependency list changed?
Does the actual hardware now function?

That final question matters.

The objective isn’t simply to eliminate a yellow warning icon. The objective is to determine whether the complete hardware stack is operating correctly.

If Code 51 Still Won’t Go Away

If you’ve already:

Restarted Windows
Examined the dependency information
Checked other failed devices
Used PnPUtil to identify problem devices
Checked Windows Update
Installed appropriate manufacturer drivers
Updated applicable BIOS and firmware
Reinstalled the affected device
Verified supporting controllers

and Code 51 remains, stop repeatedly reinstalling the same driver.

At this point, deeper investigation of the device that hasn’t started is likely to be more useful.

Check the Device Installation Logs

Windows maintains detailed logs relating to device and driver installation.

One particularly useful file is:

C:\Windows\INF\setupapi.dev.log

When to Suspect a Firmware or Hardware Problem

Code 51 by itself does not prove that the hardware has failed.

The error specifically means Windows is waiting for another device or set of devices to start. That means the device displaying Code 51 may only be a symptom of a problem somewhere else in the dependency chain.

Firmware or hardware becomes more likely when:

The correct manufacturer-provided driver stack has been installed.
BIOS and applicable firmware are current.
The same dependency consistently fails to start.
The device intermittently disappears entirely from Device Manager.
Manufacturer hardware diagnostics report a failure.
The issue persists after Windows and the driver stack have been repaired or reinstalled.
The manufacturer’s own diagnostic environment cannot initialize the hardware.
The problem began after physical damage, overheating, liquid exposure, or a hardware repair.

At that point, manufacturer diagnostics or hardware service may be more productive than another round of driver installations.

A Real-World Example: Integrated Laptop Cameras

Integrated laptop cameras are a good example of why Code 51 can be misleading.

The camera can appear in Device Manager while the Windows Camera app still cannot use it.

The device displaying Code 51 may actually be waiting for another component in the imaging stack.

Depending on the computer and hardware platform, that can include:

Camera controllers
Platform devices
Imaging components
MIPI-related devices
Firmware
Other supporting system devices

In this situation, repeatedly reinstalling only the entry named Integrated Camera may never address the underlying problem.

A better troubleshooting workflow is:

Record the dependencies associated with Code 51.
Identify the corresponding devices in Device Manager.
Check those devices for their own problem codes.
Update the complete manufacturer-provided camera and platform driver stack.
Check for relevant BIOS or firmware updates.
Restart Windows.
Verify each component in the dependency chain.

The same principle applies to other integrated hardware where several devices work together to provide one visible feature.

Useful Commands

Show Plug and Play Devices Currently Reporting Problems

Open Terminal as Administrator and run:

pnputil /enum-devices /problem

This returns Plug and Play devices that currently have problem codes.

Compare the results with the warning devices you found in Device Manager.

Examine a Specific Device Instance

If you know a device’s instance ID, run:

pnputil /enum-devices /instanceid "<device-instance-id>"

To find the device instance path:

Open Device Manager.
Right-click the device and select Properties.
Select the Details tab.
Open the Property menu.
Select Device instance path.

Copy that value and use it with the pnputil command.

Open Device Manager Directly

On your keyboard press: Win + R

Enter: devmgmt.msc and press Enter.

Final Thoughts

Device Manager Code 51 is best approached as a dependency problem, not simply as a driver problem.

Windows is telling you that the affected device is waiting for another device or set of devices to start.

That changes the troubleshooting strategy.

Instead of repeatedly updating or reinstalling the device displaying Code 51, work backward through the dependency chain:

Examine the dependency information associated with the affected device.
Identify other devices reporting errors.
Check the relevant platform and chipset components.
Install the correct manufacturer-provided drivers.
Check relevant BIOS and firmware updates.
Reinstall the affected device when appropriate.
Examine SetupAPI logs if normal troubleshooting doesn’t expose the underlying failure.

The device displaying Code 51 may only be the symptom.

Finding the component that failed earlier in the startup chain is often the key to actually fixing the problem.