To friends with macs: If you don't know about this already, it just might spare you a lot of hassles. T'was a hard-earned lesson!
Recently, after updating to OS 10.4.9, I shut down my computer and started it up the next day, only to find all content (about 100 GB of sound libraries) on my external HD had disappeared. A warning popped up saying something like "This disc cannot be read by your computer." The place I would normally click on to repair or restore it was greyed out and therefore inaccessible. My "Mac Repair" friend had no luck either. (This was especially frustrating as I was looking forward to playing some newly-installed sounds!)
The HD is a Glyph, considered excellent for music, and quite new. When I called the company, they said there is a problem with OS 10.4 (nothing prior to that), and this happened to maybe 1 out of 50 people when they update and do not first "eject" the external HD. (I hadn't even known it could be ejected.) One way to do this is command/e. It sounds like the same problem could occur for any external firewire HD. There's even info about it with recommendations on their website--www.glyphtech.com. Fortunately, they have special tools to recover otherwise irretrievable data and offer a free 2-year data recovery serivce, so I sent it off last week. (Oh, the travails of modern technology....)
Re: How to avoid external HD crash in OS 10.4 update
I've got a Glygh 550 G drive working just fine with 10.4.9 - as far as I know!
Thanks for flagging this up, it will help somebody out I'm sure. I'm sure I'm not the only one who relies on this kind of post for this type of information. You're not going to find out in your friendly local music store are you?