Hi Edward,
all projects of my application are compiled using unicode.
Boost itself was compiled for Visual Studio 2012 as follows:
b2.exe --toolset=msvc-11.0 threading=multi link=shared runtime-link=shared variant=debug
b2.exe --toolset=msvc-11.0 threading=multi link=shared runtime-link=shared variant=release
Other than changing the msvc version number due to upgrading from Visual Studio 2005 to 2012, I have used these same compile options for years.
Is there any further information that I can provide that might help diagnose the problem?