It's a new (couple of months) 2TB LaCie quadra drive. It doesn't buzz all the time, just sometimes (like now, when it started buzzing on startup. Other times it's quiet on startup and then starts buzzing for a couple of minutes and then generally stops after a bit).

Do I need to freak out?

The main question is: do you want to take the risk it's something to worry about?

If it's about really important data, I would make a backup anyway. Maybe it's nothing to worry about, but it's like insurances: maybe you'll never have a problem, but if you do and you aren't insured.... you're scr*wed.

I also have a Lacie who buzzes once in a while, but no important data is on it. The drive still works though, and I bought it in january 2006.

My hard drives do that and it annoys me, but moving them over a little usually stops the noise immediately.

I'll take a bold step and suggest that the sound you hear is the cooling fan in the unit. Sometimes the fans are slightly unbalanced and will make noise until they warm up. If the noise is livable it's your choice. I had a new drive that the drive light went out and then it lost it's FireWire identifier tag but it still worked. Rather then get stuck in a jam if the drive ever failed, I replaced it immediately.

I would also guess that it's a bad fan. As others have said, it might be nothing or it might be a big problem. Heh, I have an ioMega external drive that used to make a terrible fan noise. Then one day it just stopped and has been quiet ever since.

After leaving the drive on for an extended period, it doesn't seem to be getting warm so I have chosen to just ignore the problem. Probably, the fan has died completely. So I am taking a calculated risk. You will have to decide whether you are willing to do the same...

At minimum, if there's something important on that drive, I suggest that you do a full backup.