'Illegal operation' error messages

Helpline Q&A Directory

All too often I get an error message saying 'This program has performed an illegal operation and will be shut down', after which the program I'm using closes. How can I prevent this?

There is no way to completely free yourself of illegal operation messages, but if you're getting a lot of them you need to figure out what's causing the problem and what you can do to fix it.

If it's always the same program that goes down it's probably a bug in that program - especially if it always crashes under similar circumstances. Next time it happens, click the error message's Details button. You'll get something like 'Excel caused an invalid page fault in module fm20.dll at 0137:60007585' - not very useful for most of us. But if the vendor knows about the bug, those unfriendly numbers will help you figure it out.

Visit the vendor's website and search for the words 'illegal operation' or the numbers from the Details box. With some luck, you'll be able to locate a patch or a workaround.

If you're getting illegal operation messages from a number of programs, or if you can't fix the problem through the vendor's website, a driver may be at fault. Printer and video drivers often cause illegal operations in other programs. In the case of printer drivers, you need not even be printing for the problem to occur.

Updating the driver may do the trick. Or you can try going the opposite route and use a more generic driver. For instance, most laser printers will work with an HP LaserJet Series II or LaserJet III driver. These have been around for a long time and all the kinks are pretty much ironed out.

Video drivers are iffier. You could use VGA, but you're limited to 640x480 resolution. Even SuperVGA may dock you with that limitation. Sometimes there's a driver for a specific chip, like the S3, but in that case you have to know what chip drives your video card.