I built the WDK samples of pcidrv and ndisedge(6.0) in longhorn x86 build environment of WDK, and used the netdrv.inf to install them in Vista Business. ndisedge.sys is loaded as the upper filter driver of pcidrv, and the DriverEntry() is called. However, the MPInitialize() never been called, instead, MPUnload() in ndisedge.sys is called and the filter driver is unloaded. pcidrv.sys itself is working Ok. Anyone has suggestion what I did wrong ? build or install ? or the ndisedge.sys itself has problem ?