The blue screen of death is a critical error screen displayed by the Microsoft Windows and ReactOS operating systems in the event of a fatal system error. It indicates a system crash, in which the operating system has reached a critical condition where it can no longer operate safely.
The Blue Screen of Death in Windows 11 builds prior to 22000.348, which uses an all-black screen except for the QR code, which remained in blue.
In computing, a crash, or system crash, occurs when a computer program such as a software application or an operating system stops functioning properly and exits. On some operating systems or individual applications, a crash reporting service will report the crash and any details relating to it, usually to the developer(s) of the application. If the program is a critical part of the operating system, the entire system may crash or hang, often resulting in a kernel panic or fatal system error.
A kernel panic displayed on an iMac. This is the most common form of an operating system failure in Unix-like systems.
A display at Frankfurt Airport running a program under Windows XP that has crashed due to a memory read access violation
A kernel panic as displayed in OS X Mountain Lion
