Oh - and if you need to run a defrag using eseutil and don't have enough space left on the drive -
you can do it to a different partition. So either add an IDE drive or an external USB drive, or even do it across the network to a mapped drive. It will be slow, but it will work. Make absolutely sure you have a good backup of the store before you do so. Also, this will take extra time than a usual defrag because you are working with the limitations of how quickly the data can move back and forth. If you have a store that is many multiple gigs, plan for the moving of the data to the temp location, and then back from the temp location. I had to do this a bunch of times at my old work as well.
Thing is, I have done this a lot in exchange 2k, but never in exchange 5.5 so I hesitate to go through all the switches as they would be different in some cases. Here's a microsoft article on eseutil though that has some 5.5 mentions.
http://support.microsoft.com/default...Product=exch2k