It did not occur to me that they would not have supplied you with the debug version of the library (you sure you downloaded everything they offered?). As you discovered, the d on the end of _MDd_ indicates a library compiled with -MD plus debug (something like -Od -Zi, IIRC). You'll have to keep an eye on what happens when you want to compile your own code with debug, which you're sure to want to do, yet link with Pylon compiled for release. I don't know, you may have problems at runtime where your stuff wants the C/C++ debug libraries/DLLs while Pylon wants the non-debug ones. I don't know whether Pylon gives you their sources so that you can compile those for debug too.