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critical HP
Error Code LED blinks Red four times and white two times (POST error E0)
Processor thermal protection activated: Fan malfunction or blockage.
? What Causes This
A fan may be blocked or is not turning.
✓ How to Fix It
Ensure fans are connected and the heat sink properly attached to processor, and check for vent obstruction. If necessary, replace faulty part.
Source: page 58 of the official manual
From the manual
This error code appears in:
HP Prodesk 600 G4 Desktop Mini PC