We haven't tested the upper bound of max storage space. There is one limitation to be aware of. User's email folders consist of GRP files, one for each day. These files cannot exceed 2.2-2.4gb. This effectively limits the amount that each folder can receive per day to 2GB.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com