After many debug builds, I am trying to build a "release" version -- sometimes known as a non-debug build or retail version. In any event, despite changing my .inc file to not use the following debug library, and doing a "build clear" (which is roughly equivalent to a rebuild all), I get the following: LINK : fatal error LNK1104: cannot open file 'libboost_date_time-vc90-mt-gd-1_37.lib' I tried to change the include libraries so that libboost_date_time-vc90-mt-1_37.lib was used instead. Am I required to rebuild the entire Boost system (e.g. using "jam" files) when I want to swtich from debug to release? Can anyone think of any obvious solution to this problem? Note: I obtain the Boost lists via digests, so it may take a while for me to interactively respond, if that becomes needed. Thanks Again, Sincerely, Joseph AMDG Joseph A. Marks PHONE: 612-788-9658 e-mail: josephamarks@yahoo.com