What Is a POST Error Message?

If the PC encounters an issue while booting up, the BIOS will generate a POST error message that appears on the monitor

By
Tim Fisher
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Tim Fisher
Senior Vice President & Group General Manager, Tech & Sustainability
  • Emporia State University
Tim Fisher has more than 30 years' of professional technology experience. He's been writing about tech for more than two decades and serves as the SVP and General Manager of Lifewire.
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Updated on May 30, 2023

A POST error message is an error displayed on the monitor during the power-on self test if the BIOS encounters some kind of problem while starting the PC.

It will only display on screen if the computer is capable of booting this far. If an error is detected before this point, a beep code or POST code will be generated instead.

POST screen example showing a BIOS version number
POST screen with BIOS version.

POST error messages are usually fairly descriptive and should give you enough information to begin troubleshooting whatever problem the POST found.

Troubleshooting POST Errors

If you're seeing POST error messages, then the problem is very likely related to some sort of hardware malfunction. A stop at this step in the boot-up process means the computer hasn't even loaded the operating system, so POST errors aren't related to Windows, macOS, or Linux.

See How to Fix Stopping, Freezing, and Reboot Issues During the POST for a troubleshooting guide on what to do when your computer hangs during the post.

A POST test card displays errors during the POST, and is useful if the hardware issue occurs before the monitor can show the error.

Other Names for POST Error Messages

A POST error message is sometimes called a BIOS error message, POST message, or POST screen message, but they all refer to the same thing.

Although completely unrelated to hardware and therefore not covered in this article, a "post error message" can also refer to problems that come up while trying to upload/post information online, such as to a social media account.

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