An application crash occurs when a software program unexpectedly stops working, often resulting in the loss of unsaved data. This can happen due to various reasons, such as coding errors, memory overload, or compatibility issues with the operating system. When an application crashes, it may display an error message or simply close without warning. Users can often prevent crashes by keeping their software updated and ensuring their devices meet the necessary system requirements. Additionally, regularly saving work and using reliable applications can help minimize the impact of potential crashes on productivity.