When you installed Exchange IMF as an independent tool (version 1), it came with performace counters to allow you monitor and therefore tune the SCL levels used in the filter. The version that comes built into Exchange SP2 (microsoft call this version2) seems to be missing these performance counters. Does anyone know how to tune IMF version 2? Where these counters have gone? Or even better does any one know where I can get Documentation on IMF version 2. www.microsoft.com/exchange/imf only refers to the older independent tool version 1. Thanks