System error dialog box

The system error dialog box is presented when an unrecoverable error occurs in classic Mac OS.

Dialog box
From System 1 through Mac OS 9, the Macintosh Toolbox contained an error handler that, when an OS-level error was triggered, would launch the built-in debugger and passed it the error. If no advanced debugger such as MacsBug was installed, MiniBug would be triggered and would present a dialog box with a bomb icon in the upper left corner of the window, and the text "Sorry, a system error occurred. ID= ". The number would be a pre-defined system error code that could be looked up in the Apple Toolbox developer documents.

Though each error has an associated number, object name, and localized text description, Apple only embedded the number for most errors, even in later versions of the OS where the amount of memory used would have been trivial.

Common errors

 * -192 - Resource not found (usually after the file has been transferred via a file system that doesn't support resource forks)
 * 10 - Instruction not found in the 68k instruction lookup table.
 * 15 - Segment loader failed to load a part of the application code into memory

Recovery
Though the system error dialog box can present a resume button, it is often grayed out. It is possible to invoke the debugger through  (or a programmer's key) to enter commands to force quit the application that has caused the error condition. If the crash occurs while loading a extensions in Mac OS 8.6 or later, the dialog box will advise the user to "temporarily turn off extensions, restart and hold down the shift key" to enable an early form of safe mode.