I have found my way around the problem, though I don't understand why it works. Recap of the problem (for those joining late): attempting to build boost with bjam under msys/mingw resulted in very strange behavior. Within the msys shell, invoking the following line: bjam -sTOOL=mingw install ...resulted in bjam attempting to use the VC7 toolset. I checked the path within msys to make sure I was running the version of bjam.exe that I thought I was. Looking through the directories showed there was indeed only one copy. On a hunch, I moved it from it's present location at 'c:/msys/1.0/bin' to 'c:/msys/1.0/mingw/bin' and tried again. And suddenly bjam began using gcc. 8^0 Apparently where you run it from makes a big difference. I'm sure that an msys guru could take one look at the symptoms and say, "Of course! It's obvious to the meanest intellect!". Not being an msys guru I will just shrug my shoulders and move forward :) All is well now and Boost is building even as I type this message. Many thanks to those who replied! Best regards, Chris Brewer (Company-mandated disclaimer) This message originates from WMS Gaming Inc. It contains information which may be confidential or privileged and is intended only for the individual or entity named above. It is prohibited for anyone else to disclose, copy, distribute or use the contents of this message. All personal messages express views solely of the sender, which are not to be attributed to WMS Gaming Inc., and may not be copied or distributed without this disclaimer. If you received this message in error, please notify us immediately at (847) 785-3000.