Compiling under VS2012
From Valve Developer Community
Using Visual Studio 2012 is possible for Source. However it is not possible to use Visual Studio 2012 with the Source 2013 code base. You can use the free C++ Express edition for the 2007 code base and below.
Bug: Converting the Alien Swarm server project to VS2012 will lead to an "invalid characters in path" error. To fix it, open game\server\swarm_sdk_server.vcproj with a text editor and delete "'
$File" from line 2232. Bug: Compiling the 2013 code base with any version of VS2012 is not possible at this time. You can, however, use the VS2012 interface with the VS2010 compiler.- With the default VS2012 settings, linking some projects will fail with "Error lnk2026: module unsafe for safeseh image". This seems to happen when you try to link to libraries that were compiled with different versions of the compiler. As a workaround, set the linker option /SAFESEH[:NO] .
