Crash (computing) facts for kids

In computing, a crash happens when a computer program, like an app or the operating system itself, suddenly stops working correctly and closes. Sometimes, a special service will report the crash details to the people who made the program. If the program that crashes is a very important part of the operating system, the whole computer might stop working or freeze. This is often called a kernel panic or a fatal system error.
Most crashes happen because of a software bug. A bug is like a mistake in the program's code. For example, the program might try to use a part of the computer's memory that it's not allowed to. Or it might try to do an instruction that doesn't make sense. The original mistake that causes the crash can sometimes be hidden deep in the program's code. Finding these bugs is called debugging.
Sometimes, a crash can be used by a bad program or a hacker to take control of your computer. This can allow them to spread viruses or steal your private information.
Contents
App Crashes

An app usually crashes when it tries to do something the operating system doesn't allow. The operating system then sends a special signal to the app. On some computers, the app might show a message box asking if you want to send a report. Other apps might try to fix the problem and keep running instead of closing.
Sometimes, an app is even designed to crash if it finds a very serious error.
Here are some common reasons why apps crash:
- Trying to read or write information in parts of the computer's memory that the app isn't allowed to use.
- Trying to run special instructions that are only for the operating system.
- Trying to control hardware devices without permission.
- Giving wrong information to the operating system when asking for help.
- Trying to use other computer resources without permission.
- Trying to do math problems that don't make sense, like dividing by zero.
Crash to Desktop
A "crash to desktop" happens when a program, often a video game, suddenly closes and takes you back to your computer's desktop screen. Usually, no error message appears. The game might freeze for a moment, then just close. Sometimes, the screen might turn black, and the sound might repeat before it crashes. Other times, it might happen when you try to load a new area in a game.
These types of crashes can be very frustrating because it's hard to figure out why they are happening. Since there's no error message, it's tough to know what went wrong. Running games in a smaller window instead of full-screen can sometimes help track down the problem. Newer versions of Microsoft Windows have features that can help find the cause of these crashes.
Some programs, like StepMania, might crash to desktop in full-screen mode but then show an error message in a separate window once you are back on the desktop.
Web Server Crashes
The software that runs a web server for a website can also crash. When this happens, you might not be able to access the website at all. Or you might see an error message instead of the normal content.
For example, if a website uses a database like MySQL to show information, and that database crashes, the website might show a "connection error" message.
Operating System Crashes

An operating system crash often happens when a serious problem occurs with the computer's hardware that the system can't fix. It can also happen if the operating system finds a mistake in its own internal workings.
Most modern operating systems, like Linux and macOS, are designed to keep working even if one of your apps crashes. This is because they keep apps separate from the main system.
Some very advanced operating systems can even recover from a crash of a critical part, whether it's due to a hardware problem or a software mistake.
Security and Privacy Concerns
When a program crashes, it might sometimes contain your sensitive or private information. Also, many software bugs that cause crashes can sometimes be used by hackers to run their own code on your computer or gain more control. For example, a bug might cause a crash, but a hacker could use that same bug to make the computer do something else instead.
See also
- Blue Screen of Death
- Data loss
- Memory protection
- Reboot
- Safe mode
- Segmentation Fault
- Undefined behavior