An application can crash for various reasons, including:

• Illegal execution of a machine or privileged instruction
• Passing invalid arguments to function calls
• Attempting to access an invalid memory address
• Performing an invalid input/output operation
• Performing an illegal mathematical operation such as a divide-by-zero operation
• Using a wrong version of a dynamic library (aka, "DLL hell" in Windows)

As a result of any of the above, an application is abruptly terminated by the operating system to prevent system instability.

During a system crash, the operating system sometimes can recover from the error by rebooting. However, crashes caused by bugs in device drivers, kernel-mode errors, malfunctioning hardware or hardware/software incompatibility may require a system update, reinstallation or even an upgrade. Otherwise, the problem may persist. In some cases, the screen turns blue and error messages are displayed on screen. This is known as the "blue screen of death" in Windows.