>I'm looking for ideas on tracking down memory leaks in an application. Here's the background. I have a VFP EXE (call it UI) that instantiates a VFP COM DLL (call it DL). DL instantiates another VFP COM DLL (call it Online Timer) and a C# DLL (call it Comms). Comms talks to some hardware.
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Are you instanciating the .NET COM component a lot or are you just holding a reference to it? Do you know if the memory is being taken by VFP or by one of your COM components? You could probably test whether it's happening in .NET pretty easily by creating a dummy/stub version of it then monitoring the memory usage.

Are you explicitly releasing the variables (or properties) in DL that access your UI?