I was trying to make a small program that uses Multi-Index and Interprocess work on a Mac and was convinced that I was doing something wrong until I tried the simple example in the Multi-Index docs and found it also fails to work on Mac but works on Linux. The example is here: http://www.boost.org/doc/libs/1_35_0/libs/multi_index/example/ip_allocat or.cpp and the problem is that boost::interprocess::open_or_create does not work -it only creates. I built the example, add a few books and then quit. When I restarted the app on Linux, it listed the books from the previous run but the Mac version did not manage to do the same. Running on Linux Redhat FC8 and Mac OSX 10.5 Cheers // Martin