Disk First Aid detected impending hard drive failure in my Maxxtor 60 GB slave hard drive. I had to move everything out but fortunately there was nothing that was too important -- just a bunch of games and unedited video. This drive was salvaged from our old iMac (graphite DV special edition) so it dates way back to 2000. In fact it was the second drive we put in the iMac now that I think of it. The original iMac HD was much smaller. Anyway it was probably damaged a long time ago and has been limping along for years. I replaced it with a 120 GB (didn't want to spend too much) Seagate HD and it sure is different now booting up, without the delays, rattling in the box and weird tones that came from the old drive!