first rid yourself of the [50]'s cause you don't need them. the string attribute tells MIDL to look for the null terminator and it does size calculations on its own. Next get rid of the typedef. MIDL doesn't need it. just use struct PATIENT_INFO { [string] wchar_t wszPatientID; [string] wchar_t wszLastName; }; Hope this helps ya out. Joseph Dempsey jdempsey@cox.rr.com Joseph.Dempsey@thermobio.com "Software Engineering is a race between the programmers, trying to make bigger and better fool-proof software, and the universe trying to make bigger fools. So far the Universe in winning." --anonymous