I know that FireWire is hot-swappable, but when you're talking about FW data storage, like external hard drives, you need to unmount the drive volume(s) before you unplug them, to make sure the Mac isn't writing to the drive when you unplug it, possibly corrupting your data or some even writing to the wrong place on the drive making the drive unmountable in future. But what about in sleep? I have MacBook connected to a USB2 hub, an external FW drive with 2 partition volumes one of which is my Time Machine partition, an external display, and of course power adapter. This is a higher-end external FW drive, and when I put the MacBook to sleep, even though the FW drive has its own power supply, it detects the host device is asleep, it spins down the actual disk drive and goes into a low, low power mode, essentially it turns itself off while the MacBook is asleep, turning itself back on when I wake the MacBook. I'm in the habit, when I want to use the laptop as, well, as laptop, like first thing in the mornings, of yanking all the cables while the MacBook is still asleep. I start with the FireWire drive, to make sure the MacBook doesn't come out of sleep before I've disconnected the FW drive. Pulling the mini-DVI to DVI-adapter never seems to wake the MacBook, but pulling the USB hub and USB device connected to the two ports does. Pulling the FW drive doesn't ever wake either the MacBook or the "turn on" the FW drive, but I pull it first just in case. I always get the "device improperly removed/your data may be corrupted" dialog when I wake the Mac, because the FW drive volumes were mounted at sleep, and then on wake just poof aren't there. But since putting the MacBook to sleep does all the clean up of unmounting the FW volumes, essentially does "unmount" them but remembers they were mounted so it immediately remounts them when it wakes, and of course a sleeping MacBook can't possibly be writing anything to a sleeping external FW drive, I figure I'm perfectly safe. It just makes me nervous, the warning dialog, since it's my back-up drive. Logically I know the dialog is only triggered because the volume(s) were mounted when the MacBook went to sleep, and nothing can possibly be writing to the external drive when both Mac and FW drive are asleep, I *always* pull the external FW drive first -- it never wakes the MacBook or the drive, but even if it did, the drive would already be physically disconnected before the MacBook could write to it. Still makes me nervous, but it's a hassle to wake the MacBook, unmount the drive volumes, then put the MacBook back to sleep before pulling the external display, so the MacBook will cleanly switch to the internal display. Be helpful if someone backed me up on this: pulling a FireWire hard drive while it is "still mounted" but spun down/asleep and the MacBook is asleep may cause the warning dialog, but it's perfectly safe.