Windows Update fails with 0x800706BA (RPC server unavailable)

The problem: Windows Update cannot communicate with the Windows Update service due to RPC (Remote Procedure Call) service issues.

Symptoms: Update fails with 0x800706BA; 'RPC server is unavailable'; Update service unresponsive; updates don't download.

Likely cause: RPC service disabled or crashed; Windows Firewall blocking RPC; corrupted Windows Update components; antivirus blocking service communication.

Category: Windows Update · Difficulty: Moderate · Windows: Both · Error code: 0x800706BA

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