Gray Screen of Death

A Gray Screen of Death, also known as Gray Screen Error, Frown Error, Crying Face Error, Grey Screen or GSoD, is an error displayed in Unify Desktop after a fatal system error, also known as a system crash: when the operating system reaches a condition where it can no longer operate safely.

History
GSoDs existed in TOS 1.0 and newer versions released afterwards. Until TOS 6, the error message was put on a gray background, hence the name "Gray Screen of Death", and until TOS 5 there's a similar screen if you Ctrl+Alt+Del without any unresponsive applications.