Hi Daniel/Joaquin, Please find my answers to your questions below, [ #include <new> int main() { int space; void* ptr = &space; new (ptr) int(); } If that works okay, try also including the headers that you use in your project to see if any of them cause it to stop working. ] Yes, a fresh project with this program works. The only new header I had to add is "boost/unordered_map.hpp". Adding that did not cause any compilation problems [ It might be an issue with precompiled headers. Someone solved a similar problem by turning them off: ] I suspected this previously, but turning this on/off did not cause any issue is stand alone programs using multi_index/unordered_map. [ Along that line, Ram, could you please verify if your project uses DEBUG_NEW somewhere? Don't forget to check for macro definitions on the project's properties window. ] I did a search for DEBUG_NEW and didnt get any results. I also saw that the only preprocessor defines we have are, WIN32 _DEBUG _CONSOLE V_DEBUG Thanks, Ram