Risks Digest is chock-full of stories of software failures but I'm a little more interested in regular commercial software that is/was a complete failure. Things that simply never worked as desired, crashed more often than you could count, corrupted your data more often than you thought was possible, etc.
With that in mind my two top mentions for this category are:
- Windows ME
- Legato Networker (circa 2000/2001)
Relatively high on my list, and a friend of mine's, is Legato Networker. Networker is a system backup program that once rivaled Veritas Backup software in the enterprise but has since shrunk. The thing I remember most about Networker was its main catalog daemon that seemed to crash pretty much every chance it got, and in doing so would completely corrupt the backup catalog forcing you to restore a previous version form tape. It got so bad we started calling the daemon the "Catalog Corruption Daemon" since that seemed to be its sole purpose in life.
I'd be interested to see what other pieces of truly abysmal pieces of software we can come up with that simply never worked as promised.