critical HP

Error Code Red LED 12 blinks every second followed by a 2 second pause

The system has failed to initialize properly or perform necessary tasks required for normal startup operation.

? What Causes This

Possible firmware corruption, hardware failure or incorrect settings preventing boot processes from completing accurately. May reflect an anomaly related specifically to POST or pre-boot sequences that fail validation checks during initialization stages.

✓ How to Fix It

Re-enter BIOS Setup using F10 key upon start-up and check for any anomalies within post routines which can be reset through default configuration reloads of NVRAM.
Ensure connections are secure between essential components such as hard drives, RAM sticks etc., before attempting another boot session.
Consult service if further measures or professional assessment is needed to resolve.

Source: page 4 of the official manual

From the manual

Manual page 4 — HP error Red LED 12 blinks every second followed by a 2 second pause

This error code appears in:

HP Elitedesk 800 G1 Small Form Factor PC