A20 Line or 8042 Gate Memory Errors

A20 Line or 8042 Gate Memory Errors

If you have arrived here through a search engine, and there’s no menu to the left click here!

Explanation: The system is detecting a failure trying to access the 21st address line, A20. This line is used to provide access to the high memory area, and is normally controlled through the keyboard controller.

Diagnosis: This is usually a problem with either the keyboard or the keyboard controller on the motherboard.


  • Troubleshoot the keyboard.
  • Troubleshoot the keyboard controller.
  • Troubleshoot the motherboard.

Notice: Windows® 95, Windows® 98, Windows® NT, Windows® 2000 and Microsoft® Office are registered trademarks or trademarks of the Microsoft Corporation.

All other trademarks are the property of their respective owners.

About Dewwa Socc