Diagnostic Service Policy Not Running: 7 Proven Fixes (2026)

You click “Troubleshoot” to fix your Wi-Fi, and instead of a solution, you get another error: the diagnostic service policy is not running. It’s the kind of circular frustration that makes you want to close the laptop and walk away. I’ve been there—and in over a decade of working with Windows services, I’ve seen this exact error derail everything from simple network diagnostics to enterprise-level hardware troubleshooting.

The good news? This is rarely a sign of hardware failure. In most cases, it’s a configuration issue, a permissions problem, or corrupted system files—all of which are fixable with the right steps. This guide walks you through seven proven fixes, from the quickest service restart to advanced system file repairs, covering Windows 7, 10, and 11.

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What Is the Diagnostic Policy Service and Why Does It Stop?

Before we dive into fixes, it helps to understand what you’re dealing with. The Diagnostic Policy Service is a core Windows service that enables problem detection, troubleshooting, and resolution for Windows components. When you run the built-in Network Troubleshooter or open Event Viewer to check system health, this service is what makes those tools work.

Think of it as the triage nurse of your operating system. It doesn’t fix everything itself, but it coordinates the diagnostic process—deciding which checks to run, which tools to deploy, and how to interpret the results. It works alongside two companion services: Diagnostic Service Host and Diagnostic System Host. If any of these three are stopped or misconfigured, the whole diagnostic chain breaks down.

The Role of the Diagnostic Policy Service in Windows

Here’s a simplified flow of how it works:

You trigger a diagnostic (e.g., Network Troubleshooter)
        ↓
Diagnostic Policy Service receives the request
        ↓
It activates Diagnostic Service Host & System Host
        ↓
They run tests and collect data
        ↓
Results are sent back to the Policy Service
        ↓
Windows displays the diagnosis and suggested fix

Without the Diagnostic Policy Service running, that entire chain collapses. The Network Troubleshooter won’t start, Event Viewer may show incomplete logs, and Windows Update can struggle to diagnose its own failures.

Common Root Causes for the Service Not Running

Over the years, I’ve traced this error back to a handful of recurring culprits:

• Corrupted system files – Often the result of an interrupted update or disk errors. This is more common than most people expect.
• Incorrect startup type – The service is set to “Manual” or “Disabled” when it should be “Automatic.” This happens more often than you’d think, especially after third-party “optimizer” tools run.
• Insufficient permissions – This typically manifests as Error 5: Access Denied. The service account doesn’t have the rights it needs to start.
• Conflicts with third-party security software – Some antivirus suites aggressively block services they don’t recognize, and the Diagnostic Policy Service is a frequent casualty.
• Dependency failures – The service relies on Remote Procedure Call (RPC) and a few others. If those aren’t running, this service won’t start either.
• Recent system updates or driver installations – A new driver can sometimes break the service’s dependencies, especially network-related ones.

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How to Fix the Diagnostic Service Policy Error in Windows 10 and 11

Let’s get to the practical part. I’ve ordered these fixes from simplest to most involved. Start with Fix 1 and work your way down—most users resolve the issue within the first two or three steps.

Fix 1: Restart the Service via Services Console (services.msc)

This is the first thing I try when I encounter this error. It’s quick, non-invasive, and surprisingly effective.

1. Press Win + R, type services.msc, and hit Enter.
2. Scroll down to Diagnostic Policy Service.
3. Check its status. If it says “Stopped,” right-click it and select Start.
4. Right-click again, select Properties, and set Startup type to Automatic.
5. Click Apply, then OK.
6. Restart your PC and check if the error persists.

In my experience, this fixes the issue about 30% of the time. If the service starts but stops again shortly after, or if it won’t start at all, move on to Fix 2.

Fix 2: Run the System File Checker (SFC) and DISM

Corrupted system files are the next most common cause. Windows has built-in tools to find and repair them.

1. Open Command Prompt as Administrator (right-click Start > “Terminal (Admin)” or “Command Prompt (Admin)”).
2. Run sfc /scannow and wait for it to complete. This checks for integrity violations in system files.
3. If SFC finds issues but can’t fix them, run DISM /Online /Cleanup-Image /RestoreHealth. This repairs the system image itself.
4. Reboot after the scan completes and verify the fix.

A quick note: SFC can take 10–15 minutes on older machines. Don’t interrupt it. And if DISM fails, you may need to specify a source path using a Windows installation media—but that’s a more advanced scenario.

Fix 3: Grant Network Service and Local Service Permissions (For Error 5)

If you’re seeing Error 5: Access Denied when trying to start the service, this is the fix you need. It’s a bit unusual, but it’s been a reliable solution in my experience.

Open Command Prompt as Administrator and run these two commands:

net localgroup Administrators /add networkservice
net localgroup Administrators /add localservice

This grants the Network Service and Local Service accounts administrative privileges. I’ll be honest: this is a somewhat heavy-handed approach, and it does elevate permissions beyond what’s strictly necessary. If you’re security-conscious, you can revert these changes after the service starts by running:

net localgroup Administrators /delete networkservice
net localgroup Administrators /delete localservice

I’ve seen this fix work on Windows 10 and 11, particularly after a recent update changed default permissions. Just be aware that it’s a workaround, not a permanent solution.

Fix 4: Update or Roll Back Network Drivers

Outdated or faulty network drivers can trigger this error, especially if the issue started after a driver update.

1. Press Win + X and select Device Manager.
2. Expand Network adapters.
3. Right-click your Wi-Fi or Ethernet adapter and select Update driver.
4. Choose Search automatically for drivers. If Windows finds nothing, try Browse my computer for drivers > Let me pick from a list of available drivers on my computer, and select an older version.

If the error started right after a driver update, roll back instead: right-click the adapter > Properties > Driver tab > Roll Back Driver.

For the most reliable results, I recommend downloading drivers directly from your hardware manufacturer’s website (Intel, Realtek, Qualcomm, etc.) rather than relying solely on Windows Update. It’s an extra step, but it often resolves issues that Windows Update misses.

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Advanced Fixes for Persistent Diagnostic Policy Service Errors

If you’ve made it this far and the error is still there, don’t give up yet. These next fixes are a bit more involved, but they address deeper system issues.

Fix 5: Use the Windows Update Troubleshooter

This might sound counterintuitive—you’re trying to fix a diagnostic service, and I’m suggesting another diagnostic tool. But the Windows Update Troubleshooter is a different beast, and it can resolve underlying issues that block the Diagnostic Policy Service.

1. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters.
2. Select Windows Update and run the troubleshooter.
3. Follow the on-screen instructions and restart your PC.

This is particularly effective if the error appeared after a failed Windows Update. The troubleshooter can clear corrupted update cache files and reset update components, which sometimes restores the diagnostic service as a side effect.

Fix 6: Reset Network Settings via Command Prompt

This fix resets the entire network stack, which can resolve underlying connectivity issues that trigger the diagnostic service error.

Open Command Prompt as Administrator and run these commands in order:

netsh winsock reset
netsh int ip reset
ipconfig /flushdns

After executing all three, restart your system. This is a more aggressive fix—it will reset your network adapters to their default settings, so you may need to reconnect to Wi-Fi networks afterward. But it’s a solid solution for persistent network-related diagnostic failures.

Fix 7: Perform a System Restore or In-Place Upgrade

If nothing else has worked, it’s time to consider system-level recovery options.

System Restore is the less invasive option:

1. Type “System Restore” in the Start menu and open Create a restore point.
2. Click System Restore and choose a restore point from before the issue started.
3. Follow the wizard and restart.

If you don’t have a restore point, or if System Restore fails, an in-place upgrade is your next option. This uses the Windows Media Creation Tool to reinstall the OS while keeping your files and applications intact. It’s a longer process—expect 30–60 minutes—but it effectively repairs the entire Windows system image.

Before attempting either method, back up your important data. I’ve seen both procedures go smoothly, but it’s better to be safe.

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Should You Disable the Diagnostic Policy Service? Risks and Considerations

I understand the temptation. The service keeps throwing errors, so why not just turn it off? I’ve had users ask me this, and the answer is always the same: don’t.

What Happens If You Disable the Service?

Disabling the Diagnostic Policy Service has cascading consequences:

• The built-in Network Troubleshooter stops working entirely. You lose the ability to automatically diagnose and fix network issues.
• Event Viewer becomes less useful. The service is responsible for logging diagnostic information, and without it, you’ll miss critical system health data.
• Third-party diagnostic tools may fail. Many system utilities rely on Windows’ diagnostic framework, even if they don’t explicitly say so.
• Windows Update troubleshooting becomes harder. While the service isn’t directly required for updates, it helps identify and resolve issues that block them.

In short, disabling the service doesn’t fix the problem—it just hides it. The underlying issue remains, and you lose valuable diagnostic capabilities in the process. I’ve never encountered a scenario where disabling this service was the right call.

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Frequently Asked Questions

What is the Diagnostic Policy Service?

The Diagnostic Policy Service is a core Windows service that enables problem detection, troubleshooting, and resolution for Windows components. It coordinates the diagnostic process for the Network Troubleshooter, Event Viewer, and other built-in tools. It depends on services like Remote Procedure Call (RPC) to function correctly, and it’s essential for maintaining system health.

Why does the diagnostic service policy keep stopping?

The most common reasons are corrupted system files, incorrect service permissions (often leading to Error 5), conflicts with third-party security software, and dependency failures. A recent system update or driver installation can also trigger the issue. To pinpoint the exact cause, check Event Viewer for error logs related to the service—look for entries under “Windows Logs” > “System” with the source “Service Control Manager.”

Is the diagnostic service policy needed for Windows Update?

Not directly, but it helps. The Diagnostic Policy Service can identify and resolve issues that block Windows Update, such as network connectivity problems or corrupted update components. Disabling it won’t stop updates from installing, but it will make troubleshooting update failures significantly harder.

How do I fix the diagnostic service policy is not running on Windows 11?

Start with Fix 1 (restart the service via services.msc) and Fix 2 (run SFC and DISM). If those don’t work, try Fix 3 (grant Network Service and Local Service permissions) and Fix 5 (Windows Update Troubleshooter). Windows 11 users often find success with the network reset commands in Fix 6. For persistent issues, consider the in-place upgrade in Fix 7.

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Final Thoughts

The the diagnostic service policy is not running error is frustrating, but it’s rarely a sign of a dying machine. In my experience, most users resolve it within 30 minutes using the first three fixes. Start simple, work your way up, and don’t skip the system file checks—they’re the most common root cause.

If you’ve tried all seven fixes and the error persists, it may be time to consult a professional. There are edge cases—rare permission conflicts, deeply corrupted system images, or hardware-level issues—that require hands-on diagnosis.

One last thing: if you found this guide helpful, share it with someone who might be facing the same issue. And if you’ve got a fix that worked for you that I didn’t mention, leave a comment below—I’m always curious to learn about new approaches. For more Windows troubleshooting tips, subscribe to our newsletter.