Windows Update Error 0x800706BA — RPC Server Unavailable Fix

What Does This Error Mean?

Windows Update error 0x800706BA means the RPC (Remote Procedure Call) server is unavailable. RPC is how different Windows services communicate with each other. Think of it like an internal telephone system inside Windows — if the telephone exchange is down, services cannot reach each other. Windows Update relies heavily on RPC to coordinate its services, so if RPC is broken or blocked, updates fail.

Affected Models

Windows 10
Windows 11
Windows 8.1
Windows Server

Common Causes

The Remote Procedure Call (RPC) service is stopped or has crashed
A firewall or security application is blocking the internal RPC ports Windows uses
Windows network-related services that RPC depends on are not running
Corrupted Windows service registration entries are preventing RPC from starting properly
Malware has disabled the RPC service to disrupt Windows Update and system functions

How to Fix It

Verify the RPC service is running. Press Windows key + R, type services.msc, and press Enter. Find 'Remote Procedure Call (RPC).' It should be Running and set to Automatic. If it is stopped, right-click and click Start.

Also check 'RPC Endpoint Mapper' — it should also be running. Both are required for Windows Update to work.
Restart dependent services. In the services list, also check that these are running: Windows Update (wuauserv), Background Intelligent Transfer Service (BITS), and Cryptographic Services. Start any that are stopped.

RPC problems often cause a cascade of service failures. Restarting all these services together resolves most cases.
Run the Windows Update Troubleshooter. Go to Settings > System > Troubleshoot > Other troubleshooters and click Run next to Windows Update.

The troubleshooter automatically checks service status and can restart RPC-dependent services.
Temporarily disable your firewall and retry. If you have a third-party firewall (not just Windows Defender Firewall), try disabling it briefly and running Windows Update again.

Third-party firewalls can block internal RPC communications. If updates work with the firewall off, add an exception for Windows Update in the firewall settings.
Run System File Checker to repair RPC-related system files. Open Command Prompt as Administrator: sfc /scannow — followed by: DISM /Online /Cleanup-Image /RestoreHealth

Corrupted system files can cause the RPC service to fail silently. These commands restore them.

When to Call a Professional

If you cannot get RPC services running after trying these steps, a technician can use specialized tools to repair Windows service registrations. This is especially common in managed business environments where group policies control services.

Frequently Asked Questions

What is RPC and why does Windows Update need it?

RPC (Remote Procedure Call) is a core Windows communications mechanism that lets different services and programs call functions in each other. Windows Update uses multiple separate services that must communicate constantly — the update scanner, the downloader, the installer, and the notification system. All of these talk to each other over RPC. If RPC is unavailable, these services cannot coordinate, and updates cannot proceed.

Could malware disable RPC?

Yes. Some malware specifically disables RPC and Windows Update services to prevent the system from receiving security patches. If RPC is disabled and you cannot find why, run a full malware scan with Windows Defender and Malwarebytes. Check the RPC service startup type — if someone or something set it to Disabled, that is a red flag.

This error appeared after I installed new security software. Is that the cause?

Very possibly. Some aggressive security products block RPC traffic as a precaution. Try temporarily disabling the new security software and retrying Windows Update. If that fixes it, configure the security software to allow Windows Update and RPC traffic, or contact the software's support team for guidance.