While I am by no means an authority on the subject, what sort of external do you have? I take it your G3 is using USB 1.1, but maybe not (firewire?). The obvious things would be to make sure your cables are attached and work. Did you check your system profiler to see if it's recognized there? I'm having similar problems, but only with an external cd-rw. I was told to disable various authoring extensions through extensions manager, and while that helped with some issues, the machine still does not recognize the external drive. in my case, i think Toast is the culprit, but not sure. I'd be happy to share the disable instructions i got from apple support/discussins if you'd like.