Have you ever faced an error while running Windows® operating system on your PC that says something like, “A Fatal Exception error [some error name] has occurred at [some memory address]”? When you click on the big OK button in the message window, the computer either shuts down or some program terminates instantly. The cross mark in red on the window distinguishes the error as a critical error. But why do these occur? Let’s find out.

Fatal Exception errors can occur due to many reasons. These include:

1. When a process comes across an illegal instruction set.
2. A program or Windows® comes across some invalid code or data that prevents it from running properly.
3. The application tries to access some resource that it is not authorized to access under normal circumstances.

When these problems occur with some process or application, the processor returns an error message to the operating system. The operating system in turn fires a Fatal Exception Error to notify the user about the problem. The operating system is not responsible for the error; it is concerned only with the firing of the error message and handling the corresponding error by shutting down the corresponding application or process.

Fatal Exception errors are of various types, which include:

1. Divide Fault: This error occurs when an application tries to divide some figure with zero. It can also happen when the process returns a value that it is not able to handle. These usually occur due to programming errors.
2. Overflow Trap: This error takes place when an INTO instruction, after execution, is followed by a 0F bit set to 1.
3. Bounds Check fault: This error occurs when the index of an array is out of range. The index is compared with the lower and upper bounds by the BOUND instruction. If the value is out of range, the processor traps it and displays error 05.
4. Double Fault: When an exception triggers the occurrence of a second critical exception, the phenomenon is known as a double fault. Repeated occurrences of double faults are bad news. This usually indicates that there is some serious problem in the PC.
5. General Protection Fault: This occurs when an exception that cannot be classified under any of the other exceptions takes place. This error is often seen to occur when running malfunctioning third party applications.

Fatal Exception errors are bad news, and should be taken very seriously. If you get Fatal Exceptions repeatedly, then it makes sense to get your system checked by a system engineer.