Hi everyone, After switching from BOOST 1.33.0 to 1.34.1 (and also from VS2005 -> VS2008) we got a couple of problems with "cannot instantiate abstract class" errors. The application compiles fine in the setup VS2005 + BOOST 1.33.0 but suddenly started to throw a couple of "cannot instantiate abstract class" errors when using VS2008 + BOOST 1.34.1 . The errors itself get reported for 'concept_check.hpp' but that header did not change between the two BOOST releases (as far as I know - I think I made a diff with no results). I believe that the issue is most likely related to the boost::shared_ptr's to templated classes in our code. I already solved a few of these errors that arose thanks to slightly different types in the method definitions thanks to VS2008 having more built in types. However, the current "cannot instantiate abstract class" errors are persistently eluding my grasp. And the compiler is not helpful with just reporting the error in 'concept_check.hpp' and not where it really is. Questions: Can anyone of you think of additional (compiler) switches for BOOST (or even VS2008) that could help track down these kind of the issues? Did anyone experience similar problems when switching between BOOST versions (in general)? Thanks a lot for reading this and for any advice. T