STATUS_LPC_REPLY_LOST (0xC0000253) fix for server admins

Quick answer

Restart the RPC service and the application that uses LPC (like SQL Server or Exchange). If that doesn't work, reboot the server. It's almost always a stuck LPC port or a dead RPC endpoint.

What this error actually means

You're looking at 0xC0000253, and it says the server sent messages but got no reply. In plain English, your server tried to talk to another process using LPC — Local Procedure Call. It's like a fast internal messenger between programs on the same machine. But something broke the line. The message went out, but nobody answered.

I see this most often with SQL Server (especially when linked servers are involved) or Exchange Server (when the RPC Client Access service flakes out). Had a client last month whose entire SQL Server instance went down because a linked server query hung, and the LPC pipe just... stopped. The error showed up in the System log with Event ID 7031 for the RPC service, but the real problem was the LPC port.

The trigger? Usually one of three things: a sudden restart of a dependent service (like the SQL Server Browser service), a network glitch that kills the RPC endpoint mapper, or a memory pressure situation where the LPC reply buffer gets lost in the shuffle. Windows Server 2016 and 2019 seem to be the worst offenders. Server 2022 is better but not immune.

Fix steps — do these in order

1. Restart the RPC service. Open Services.msc, find "Remote Procedure Call (RPC)". Right-click, Restart. This kills all existing LPC endpoints and rebuilds them. Note: This also restarts any service that depends on RPC, which is basically everything. So do it during a maintenance window.
2. Restart the application that's throwing the error. If it's SQL Server, restart the SQL Server service. If it's Exchange, restart the Exchange RPC Client Access service. This clears the application's specific LPC port.
3. Check for stuck LPC ports. Open an admin Command Prompt and run:

   sc queryex state= all | find /i "lpc"

   If you see any LPC ports in a "stopped" or "waiting" state, note the PID. Then run

   taskkill /PID [PID] /F

   to kill the owner process if safe.
4. Reboot the server. I know it's blunt, but this clears every LPC port and resets the RPC endpoint mapper. On Windows Server 2016, I've seen LPC ports stay locked even after restarting the RPC service. A reboot is the nuclear option that works.

Alternative fixes if the main ones fail

If restarting RPC and the app don't help, try these:

• Check for duplicate IP addresses. Run

  arp -a

  and look for duplicate MACs. A network card with the same IP as the server can mess up LPC because RPC uses TCP/IP for some endpoints. Seen it happen with a misconfigured Hyper-V virtual switch.
• Disable the RPC over HTTP proxy if it's enabled. Go to Registry Editor, find HKLM\SYSTEM\CurrentControlSet\Services\RPCHTTP, set Start to 4 (disabled). Reboot. Some Exchange setups enable this unnecessarily, and it causes LPC timeouts.
• Run a memory diagnostic. Bad RAM can corrupt LPC buffers. Use Windows Memory Diagnostic or MemTest86. Had a server once where a bad DIMM caused random 0xC0000253 errors every few days.

How to prevent it from coming back

The best prevention is to keep the RPC service stable. That means:

• Install all Windows updates, especially security updates for RPC. KB5001401 for Server 2019 specifically fixes a bug that caused LPC reply loss in high-traffic scenarios.
• Monitor the RPC service with a script. Set up a scheduled task that checks if the RPC service is running every 5 minutes. If it's not, restart it and log it.
• Limit linked server queries in SQL Server. Each linked server query creates an LPC port. If you have 50 linked servers all firing at once, you're asking for trouble. Use stored procedures instead of ad-hoc queries.
• Don't run Exchange and SQL Server on the same machine. I've seen this error spike when both services fight for LPC bandwidth. Separate them if you can.

Bottom line: 0xC0000253 is a communication breakdown inside the server. Restart the messenger (RPC), clear the line (app restart), and if that fails, reboot the whole phone exchange (server). It's not a hardware error — it's a software traffic jam. Treat it like one.