Unresolved external symbol error occurring only in 64-bit mode and not in 32-bit build

Question

I have a VC++ code (built using VS2008), which makes use of some static libraries (*.lib files linked statically during compile time).

For ease of understanding let\

Answer 1

From the looks of it, you're only changing half of your projects to x64 and leave the rest to Win32. Since you don't show your project's dependencies, its hard to guess if that's a problem or not ... in any case, for compilation to succeed you'll have to switch all of the dependent projects (libs) to x64!