I'm running W2k Pro.
I've thought about running Eraser, for unused space cleanup, in safe mode, in order to speed things up.
It seems that it would be safe, but I don't know.
Is it safe?
I use Eraser 5.7.
Safe? Yes (at least on an XP Pro system running 5.7).
But faster? No. A lot slower, here. I don't know why, but doing scans in "Safe" mode here - not just with Eraser but with just about every program I've got that "scans" - is horribly slow. (Which doesn't make a whole lot of sense, unless there's a driver that doesn't get started in "Safe" mode that all these programs need).