Yeah, this error's annoying. You're staring at a crash, a service that won't start, or an app that bombs out with STATUS_INVALID_PORT_ATTRIBUTES (0xC000002E). Let's cut the chatter and fix it.
The Quick Fix: Reboot and Clear Stale Handles
The culprit here is almost always a stale or corrupted port handle. Some app or service grabbed a Local Procedure Call (LPC) port, didn't release it cleanly, and now your app can't open a new one. The fastest way to flush those is a full system restart.
- Reboot the machine. Not a logoff, not a sleep/wake. A full restart. This kills all processes and releases every handle.
- Test the app again. If it works, you're done. If not, move to the next step.
- Check for a service that's stuck. Open
services.msc, look for any service in a 'Stopping' or 'Starting' state. Right-click and restart it. That often clears the port.
Why Reboot Works
Windows uses LPC ports for inter-process communication (IPC). Think of them like phone lines between processes. When a process crashes or doesn't clean up after itself — common with poorly written apps or buggy drivers — that port stays in a weird state. The kernel's handle table still references it, but nobody's listening. Your new process tries to connect, the kernel looks at the handle attributes, finds garbage, and throws 0xC000002E right in your face.
A reboot clears the entire handle table. Every process, every thread, every port — gone. Fresh start. It's brute force, but it's effective.
When Reboot Isn't Enough
If the error keeps coming back after a restart, you've got a recurring problem. Here's what I've seen on the job:
1. Broken Application with a Handle Leak
Some apps — especially older ones or custom in-house garbage — allocate LPC ports but never close them. Over time, they exhaust the system's port pool. The error shows up after the app's been running for hours. Fix: update the app, or if it's yours, audit the code for missing CloseHandle() calls on LPC ports.
2. Corrupted Service Dependencies
Seen this on Windows Server 2016 a lot. A service like RpcSs (Remote Procedure Call) or LanmanServer gets its dependencies out of whack. Check sc qc [service name] for any port-related dependencies. If they reference a service that's disabled or missing, fix the dependency chain.
sc qc RpcSs
sc query RpcSs
3. Antivirus or Security Software Blocking Ports
Some security suites — looking at you, McAfee and certain CrowdStrike versions — hook into LPC ports and mess with attributes. Temporarily disable the AV to test. If the error disappears, add an exclusion for your app.
4. Driver-Level Port Conflicts
Virtualization software (VMware, Hyper-V) and VPN clients sometimes grab LPC ports for their own IPC. A driver update can break the handshake. Update all drivers, especially network and virtual adapter drivers.
Advanced Diagnostic Commands
If you want to get your hands dirty before rebooting a production box, try these:
- Check handle count:
!htrace -enable [PID]in WinDbg (kernel debugger) to trace handle allocations. Look for LPC port handles that don't close. - List open ports:
netstat -ano | findstr :135(RPC end point mapper). If that port's hung, you'll see it in a weird state. - Process Explorer from Sysinternals — sort by handle type 'Port'. Any port with a blank or weird name might be the problem.
Prevention Tips
You don't wanna keep fighting this. Here's what stops it coming back:
- Keep Windows updated. I know, boring advice. But every few months, Microsoft patches handle management bugs that cause exactly this.
- Set up proactive monitoring. Get a handle count baseline for your critical services. If a service's handle count climbs over time, you've got a leak. Fix it before it hits the port limit.
- Use modern IPC. If you're writing software, don't use raw LPC ports. Use named pipes or Windows sockets. They're more forgiving and better documented.
- Restart services on a schedule. For flaky legacy apps, a weekly restart of the affected service clears the decks.
That's it. Reboot's the hammer, handle audit's the scalpel. Pick your tool and get back to work.