Windows Error 0x800706ba: 4 Ways to Fix RPC_S_SERVER_UNAVAILABLE

What Does Error 0x800706ba Mean

Error 0x800706ba is a hexadecimal system constant for RPC_S_SERVER_UNAVAILABLE. In simpler terms, Windows cannot establish a connection with the Remote Procedure Call (RPC) service. A client application (e.g., an update installer or a network printer connection) sent a request, but the RPC server component did not respond.

Typical scenarios where it appears:

• Connecting to a network printer.
• Accessing administrative shares (ADMIN$) on a remote PC.
• Installing Windows updates or programs.
• Writing events to the Windows Event Log with an RPCSS or DCOM source.

The issue is almost always related to the state of the RPC service itself, its dependencies, the network stack, or a firewall block.

Main Causes

1. RPC or DCOM services are stopped. The most frequent cause. Services may have been disabled manually, terminated unexpectedly, or failed to start after system boot.
2. Corrupted system libraries. Critical files like rpcrt4.dll or rpcss.dll are damaged or missing.
3. Corrupted network stack. Issues in the TCP/IP stack or Winsock catalog disrupt data transmission on port 135 (RPC Endpoint Mapper).
4. Firewall blocking. Inbound/outbound connections on port 135/TCP and dynamic RPC ports (>1024) are blocked by the built-in or third-party firewall.
5. Driver or software conflict. Network drivers, VPN clients, system optimization programs, or certain antiviruses can interfere with RPC operation.

Step-by-Step Solution

Step 1: Restart and Check RPC and DCOM Services

Start here. This resolves the issue in 70% of cases.

1. Press Win + R, type services.msc, and press Enter.
2. In the list, locate the three key services:
   • Remote Procedure Call (RPC)
   • DCOM Server Process Launcher
   • RPC Endpoint Mapper
3. For each service:
   • Ensure the "Status" column reads "Running".
   • If the status is "Stopped", right-click → "Start".
   • Right-click → "Properties". In the "Startup type" field, select "Automatic". Click "Apply" and "OK".
4. Close the Services window and try to repeat the action that triggered the error.

RPC and DCOM services in 'Running' state

Step 2: Repair System Files (SFC and DISM)

If the services are running but the error persists, check the integrity of system components.

1. Launch Command Prompt or PowerShell as an administrator.
2. Run the system file scan and repair:

   sfc /scannow
   

   The process will take 10–20 minutes. After completion, restart your computer.
3. If sfc did not fix errors or reported it could not perform the repair, use DISM to restore the system image:

   DISM /Online /Cleanup-Image /RestoreHealth
   

   After DISM completes successfully, run sfc /scannow again and restart.

Commands for system file repair and network reset

Step 3: Reset Network Settings (TCP/IP and Winsock)

A corrupted network stack is often a hidden cause.

1. In the open Command Prompt (Administrator), execute the TCP/IP reset command:

   netsh int ip reset
   

2. Then, execute the Winsock catalog reset:

   netsh winsock reset
   

3. Important: After running both commands, restart your computer. Changes will not take effect without a reboot.

Step 4: Check Firewall and Antivirus Settings

The firewall may be blocking the traffic necessary for RPC.

1. Temporarily disable your third-party antivirus and its firewall module (e.g., in Avast, Kaspersky, McAfee). Try the problematic action again. If the error disappears, configure exclusions in that software.
2. For Windows Firewall:
   • Open Control Panel → System and Security → Windows Defender Firewall.
   • On the left, select "Allow an app or feature through Windows Defender Firewall".
   • Click "Change settings" (administrator privileges required).
   • In the list, find "Remote Procedure Call (RPC)".
   • Check the boxes in the "Private" and "Public" columns (or at least the one corresponding to your network type).
   • Click OK and restart your PC.
3. For third-party antivirus, add an exception for:
   • Port 135/TCP (RPC Endpoint Mapper).
   • The svchost.exe process with the -k DcomLaunch parameter.

Prevention of Recurrence

• Never disable the Remote Procedure Call (RPC) and DCOM Server Process Launcher services. Stopping them will render the system unusable.
• Regularly install Windows updates. Many RPC compatibility and stability issues are fixed in cumulative updates.
• Install drivers and software only from official sources. Third-party drivers (for network adapters, VPN, virtual machines) often cause conflicts.
• When using third-party antivirus, do not completely disable its network protection modules. Instead, configure proper exception rules for RPC.