I am having a problem with b2 on Windows using Visual Studio (2010 & 2012 but it is irrelevant): Until now I was building boost with b2 in a way that would first build 32 bit version in the default library directory, then the 64bit version in lib/64 . I wasn't using the 64bit version until this morning so I didn't get any problem whatever my use of boost was. I often use Cmake these days and I set the boost environment variables for FindBoost CMake script to find it. My problem is that I'm trying now to use the 64 bit version now and CMake FindBoost script will only find the 32 bit version. CMake correctly assume that the library files in the lib directory are the one to use, however it have no apparent way to find if it is for 64 or 32 bit. Now I'm not sure how to fix this. I see two solutions but I don't see how to apply them: 1. make b2 generate lib and dll files with an additional indication on if it's 64 or 32 bit address model. I didn't find such option in b2 --help so I assume that it is not possible? 2. find a way for CMake FindBoost to automatically find the 64 bit binaries instead of the 32 bit binaris. I don't see a clear solution to achieve this, because it depends a lot on how boost have been compiled. Note: I don't want to use a default boost installation, I want to use my custom build. Any advice on how I should proceed? Thanks for your patience. Joel Lamotte