Fix 0x80320018: Too Many Boot-Time Filters

You hit the filter wall, I get it.

This error pops up when Windows won't boot—usually after you install a second antivirus, a VPN, or some firewall software. The culprit here is almost always too many boot-time filters. Windows has a hard limit (256) on how many network filters can load at startup. Once you cross it, you get 0x80320018 and a black screen.

The real fix: boot to safe mode and clean house

Boot into Safe Mode with Networking. Restart your PC, press F8 before Windows loads (or mash Shift+F8 if you have UEFI). Pick Safe Mode with Networking. If you can't get there, use a Windows install USB—select Repair your computer > Troubleshoot > Startup Settings > Enable Safe Mode.
Disable third-party security tools. Open a command prompt as admin. Run
```
sc query type= driver
```
to list all drivers. Look for anything related to antivirus (Avast, McAfee, Norton), VPN clients (ExpressVPN, NordVPN), or firewall add-ons. If you see a name like nvppc or avast!, stop it:
```
sc stop <driver_name>
```
and set it to disabled:
```
sc config <driver_name> start= disabled
```
Delete problematic boot filters. Run
```
netsh wfp show boot-time-filters
```
to see what's loaded. If you see a long list, clear them:
```
netsh wfp delete boot-time-filters
```
This wipes all third-party boot filters. Windows re-adds its own during next boot, so don't worry.
Restart normally. If the error is gone, you're done. If not, move to the next section.

Why this works

Windows Filtering Platform (WFP) has a hard limit of 256 boot-time filters. That's a kernel-level cap—can't change it. When you install multiple security tools, each one adds its own filters. Antivirus adds network scanning filters. VPNs add redirect filters. Firewalls add block rules. They stack up fast. Once you hit 256, the system refuses to boot because WFP can't load all filters. Safe mode bypasses most of them, letting you remove the extras. Deleting boot-time filters resets the count to zero, then Windows rebuilds only what it needs.

Less common variations

Windows boots but drops network

Sometimes you get past boot, but Wi-Fi or Ethernet stops working. Same root cause—too many filters. Open an admin command prompt and run

netsh wfp reset

to clear all WFP state. Then restart. If that kills your connection entirely, you have a corrupted filter store. Run

sfc /scannow

and

dism /online /cleanup-image /restorehealth

to fix it.

Error shows only after a Windows Update

Microsoft sometimes changes filter handling in patches. If the error appeared after KB502xxxx, roll back the update. Go to Settings > Update & Security > View update history > Uninstall updates. Remove the latest one. Reboot. If the error vanishes, block that update with the Show/Hide troubleshooter.

VM or container host hitting the limit

Running Hyper-V, Docker, or VMware? Each virtual switch adds its own boot-time filters. If you have more than 10-15 VMs, you can hit the cap. Reduce the number of virtual adapters. Or move non-critical VMs to a different host.

How to stop it from coming back

Stick to one security suite. Don't run Windows Defender alongside a third-party antivirus. Uninstall the extra one completely—its uninstaller usually removes the filters.
Watch your VPN client. Some VPNs (looking at you, some cheap ones) leave boot filters behind after uninstall. Use the vendor's cleaner tool. Or run
```
sc query type= driver
```
after uninstall and manually remove any leftover drivers with
```
sc delete <driver_name>
```
.
Check for app conflicts. Stuff like Wireshark, Npcap, or any packet capture tool can add filters. If you don't need them at boot, disable their startup filters in the app settings.
Don't overdo firewall rules. If you write custom WFP rules with netsh or PowerShell, keep the count under 200. Leave breathing room for Windows and your AV.

One more thing: if you're on Windows 10 22H2 or Windows 11 23H2, Microsoft raised the limit from 256 to 512 in some builds. But older builds still have the 256 cap. So if you can, update to the latest build. That alone can fix it without removing anything.