WM_COPYDATA fails in Release Build

[stj]

I'm using WM_COPYDATA to pass data between two multithreaded applications. This works fine if both of them are built in debug mode. When I'm trying to build the applications in release mode I do not get any WM_COPYDATA messages anymore. I'm not a crack in IPC programming but I hope anyone has a suggestion for me. I'm using MSVC 6.0. Both applications are multithreaded and are linked against dll's but I don't mind that this would be a problem. It would be great getting a suggestion.

Thanks for your help.

Stefan