RPC_X_PIPE_CLOSED 0x77C error fix for real this time

Quick answer for advanced users

Restart the RPC service (net stop rpcss && net start rpcss from admin cmd) and flush DNS cache (ipconfig /flushdns). If that doesn't work, check your firewall for blocked RPC dynamic ports (ports 49152-65535).

Why this error happens and why it's a pain

I've seen the RPC_X_PIPE_CLOSED (0X0000077C) error pop up on Windows Server 2016 and 2019 mostly. It happens when a Remote Procedure Call connection gets dropped before the data transfer finishes. The RPC pipe — think of it as a temporary tunnel between two machines — gets closed by the network or the receiving side. Common triggers: a backup software trying to read files over SMB, a print server talking to a network printer, or a SQL Server linking to a remote database. Last month I had a client whose file server kept throwing this error every 15 minutes during their nightly backup. Turned out their switch had a bad port causing random disconnects.

Here's the kicker: This error doesn't always point to a broken service. Sometimes it's just network congestion or a dying network card. But you gotta check the basics first.

Step-by-step fix for 0X0000077C

1. Restart the RPC services – Open cmd as admin and run:
   

   net stop rpcss && net start rpcss
   net stop rpcss && net start rpcss

   This restarts the Remote Procedure Call (RPC) Locator and RPC Endpoint Mapper. Wait 30 seconds, then test your connection.
2. Flush DNS and reset network stack – Run these commands in order:
   

   ipconfig /flushdns
   netsh int ip reset
   netsh winsock reset

   Reboot the server after this. I've had this fix work on a Windows Server 2019 box that was throwing the error every time someone opened a shared folder.
3. Check firewall rules for RPC ports – RPC uses random high ports (49152-65535) by default. Make sure your firewall isn't blocking these. On Windows Firewall, check that "Remote Service Management" and "Remote Event Log Management" inbound rules are enabled. If you're using a third-party firewall, add an exception for ports 49152-65535.
4. Disable IPv6 temporarily – Sometimes IPv6 causes RPC conflicts. Go to Network and Sharing Center > Change adapter settings > right-click your network adapter > Properties > uncheck "Internet Protocol Version 6 (TCP/IPv6)". Reboot and test. If it fixes the error, keep IPv6 off or fix your IPv6 config.
5. Check for dying hardware – If the error keeps happening, swap the network cable or check the switch port. I've replaced a faulty cable that fixed this error on a client's print server.

Alternative fixes if the main steps don't work

If you still see the error after those steps:

• Run SFC and DISM – Corrupted system files can cause RPC issues. Run sfc /scannow then DISM /Online /Cleanup-Image /RestoreHealth. Reboot after.
• Check Event Viewer for clues – Look under Windows Logs > System for Event ID 5719 or 7024. These often point to a specific service or device that's causing the pipe closure.
• Update network drivers – Old Realtek or Broadcom drivers are notorious for RPC glitches. Download the latest from the manufacturer's site, not Windows Update. I fixed a 2019 server by rolling back a driver update that broke RPC communication.
• Disable NetBIOS over TCP/IP – In advanced TCP/IP settings under WINS, select "Disable NetBIOS over TCP/IP". This can stop some broadcast conflicts that kill RPC pipes.

How to stop this from coming back

Once you fixed the error, make these changes permanent:

• Set a static DNS server on your server (use 8.8.8.8 and 8.8.4.4 if your internal DNS is flaky).
• Monitor your switch ports for errors. If you see CRC errors or collisions, replace the cable or port.
• If you use backup software (like Veeam or Acronis), schedule backups during low network traffic hours. Heavy load can cause RPC timeouts.
• Keep Windows and drivers updated. I set automatic updates to install at 3 AM on my clients' servers.

One last thing: If this error happens across multiple servers, check your network switch for a bad backplane. Had a client with 3 servers all throwing 0x77c at random times. Replaced a dying HP switch and the errors vanished. Hardware is sneaky like that.