Hi, Since upgrading this computer to OSX 10.5 (from Tiger 10.4), I've had weird boost::timer behaviour - jobs taking 50+ hours report as finishing in ~3000s. It seems similar to the problem here (elapsed_max is the problem, basically): http://lists.boost.org/boost-users/2007/09/30661.php The code in that thread gives elapsed_max() as 4294.97 sec on my system. I guess this is a bug the standard library on 10.5, not a Boost bug, but still - any ideas? Thanks, Tom