Fix NS_E_INVALID_PUSH_TEMPLATE (0xC00D151A) on Windows

What's Actually Happening Here

The error NS_E_INVALID_PUSH_TEMPLATE (0xC00D151A) means Windows tried to register a push notification channel, but the template it loaded from the registry was malformed or missing. This usually happens after a bad Windows update, a third-party app that mucks with notification settings (looking at you, certain VPN or antivirus tools), or a corrupted user profile.

Don't waste time reinstalling Windows or resetting your whole PC—this is almost always fixable with targeted steps. Let's work through them in order.

Fix 1: Restart the Windows Push Notification Service (30 seconds)

This clears any transient state in the service that might be holding a bad template. It's the first thing to try because it costs you nothing.

1. Press Win + R, type services.msc, hit Enter.
2. Scroll down to Windows Push Notifications User Service (or WpnUserService on older builds).
3. Right-click it, choose Restart.
4. Also restart Windows Push Notifications System Service (WpnService).
5. Reboot your PC.

Why this works sometimes: The push service caches template data in memory. A restart flushes that cache and forces it to re-read from the registry. If the registry data is valid but got corrupted in memory, you're done here.

Test by opening an app that uses push notifications—like Settings > System > Notifications and toggling something. If the error's gone, stop reading.

Fix 2: Clear the Notification Cache and Reset Template Data (5 minutes)

If the service restart didn't cut it, the template data stored in the registry is likely borked. We're going to delete the cached templates and let Windows rebuild them on next boot.

1. Open an admin Command Prompt: right-click Start > Terminal (Admin) or Command Prompt (Admin).
2. Run these commands one at a time:

   net stop WpnUserService
   net stop WpnService
   reg delete "HKCU\Software\Microsoft\Windows\CurrentVersion\Notifications\Push" /f
   reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Notifications\Push" /f

3. Reboot. The services start automatically and will recreate the template data from scratch.

What's really happening: Both HKCU and HKLM keys hold push template definitions. Deleting them removes whatever corrupted template Windows was choking on. On next boot, the push notification service generates fresh templates based on the installed apps' manifest data. I've fixed this exact error on three different Windows 11 23H2 machines this way.

If the error comes back after a few hours, we've got a deeper issue.

Fix 3: Check for Third-Party Interference (15+ minutes)

Some software hijacks push notification handling. I've traced this to VPN clients (especially those with their own notification systems), overly aggressive privacy tools, and even some Dell or Lenovo pre-installed utilities.

1. Boot Windows in Safe Mode (press Shift + Restart, then Troubleshoot > Startup Settings > Restart > 4).
2. Test if the error still appears. If it doesn't, it's a third-party app.
3. In normal mode, use Autoruns (from Microsoft Sysinternals) to disable startup items and services one by one. Focus on:
   • VPN clients (NordVPN, ExpressVPN, etc.)
   • Antivirus firewalls (Norton, McAfee, Bitdefender)
   • Overlay or screen-recording tools
   • Laptop manufacturer utilities (Dell SupportAssist, Lenovo Vantage)
4. Reboot each time and test.

The real trigger I've seen repeatedly: Bitdefender's VPN module on Windows 11 22H2. It registers its own push template provider and sometimes leaves a corrupt reference during uninstall or update. Removing Bitdefender entirely and using Windows Defender fixed it for that user.

Fix 4: Repair Broken App Package Registration (advanced, 15+ minutes)

If none of the above worked, the push template might be tied to a specific UWP (Universal Windows Platform) app whose manifest is damaged. The Windows Notification Platform derives templates from installed app packages—if one's broken, it pollutes the whole system.

1. Open PowerShell as Administrator.
2. Run this to find all installed packages and their notification capabilities:

   Get-AppxPackage | Where-Object {$_.SignatureKind -eq "Store"} | Get-AppxPackageManifest | Select-Xml -XPath "//*[local-name()='Notification']" | ForEach-Object { $_.Node.ParentNode.ParentNode.PackageName }

3. Look for any package with a missing or invalid notification entry. Usually it's something like Microsoft.WindowsNoticationCenter or a third-party app you recently installed.
4. Reinstall the problematic package. For example, for the notification center:

   Get-AppxPackage *notifications* | Remove-AppxPackage
   Get-AppxPackage *notifications* | Add-AppxPackage

5. Reboot.

Why this is the nuclear option: The push template is essentially an XML schema that Windows uses to map notification content (icon, title, body) to the Action Center. When a package's manifest defines a template but the package is corrupted, the system can't parse it—hence the error. Repairing the package fixes the source.

I've only needed this step twice: once for a broken Microsoft Store install and once for a user who'd uninstalled Cortana via PowerShell incorrectly.

When to Give Up and Create a New User Profile

If you've done all four fixes and the error still pops up, it's possible your user profile itself is damaged (corrupt registry hives for push notifications). Create a new local user account, log into it, and see if the error appears. If it doesn't, migrate your data and ditch the old profile. It's a pain, but it's faster than trying to repair a profile that's been rotting for years.

One last thing: check your Event Viewer under Applications and Services Logs > Microsoft > Windows > Notifications. Look for Event ID 1000 with the error text. That'll tell you exactly which app triggered it—saves you guessing.