Update 1-23-2019: This article has been updated with additional details on how to fix boot errors.
What does a “Default Boot Device Missing” error mean?
A “Default Boot Device Missing” error is a startup error you might see on your Lenovo computer. Once you turn on your PC, you expect to see the familiar Windows loading screen after the initial startup screen. But if there’s something wrong with your PC, instead of that, you might see an error message after the startup screen.
All manufacturers of PCs have slightly different terminology in their error codes, even though many of them might mean the same thing. The message “Default Boot Device Missing” is used mostly by Lenovo PCs, and almost exclusively to refer to a specific boot error. Some Acer PCs also use this error message. While some boot errors can be very serious, this one usually has a simple fix (although, as our case study below will attest, sometimes the fix is not so simple).