Not many people encounter an error when they upgrade their Macintosh System Software, since the installer ensures that certain criteria are met before the actual installation begins. Hard drive space, CPU support, disk driver version, and firmware are examined in the extensive check list. But occasionally problems do happen, which will automatically terminate the installation. (Did you know that if you created a folder called Drive Setup, and place the Drive Setup utility in that folder within the Utilities folder, a MacOS upgrade will fail!? ) You'll receive the warning, "The installation of the software was unsuccessful, leaving your hard disk untouched."* This cartoon features a young Mr. Jobs after his prom date, having experienced installus interuptus.
*I haven't encountered an installation error for quite some time, so if anyone has the exact text from the error message, please post it on the message board!