这个其实对程序来讲没有什么影响，不影响你对自己程序的调试。
具体看这个地方：
https://software.intel.com/en-us/articles/visual-studio-debugger-cannot-find-or-open-the-pdb-file
出现这个信息的原因：
文章大意是说这个不是错误消息，这个是在使用调试功能时，vs打算加载这些系统dll的pdb文件并对系统dll进行调试，而通常系统是没有这些pdb文件的，导致的结果是无法调试这些dll。但是由于这些都是系统dll，绝大多数情况下你只是调试自己的程序，而不需要调试系统dll，因此把它们忽略掉就行了。
原文如下：
These are not error messages - they are informational messages from the Visual Studio debugger listing the various executables and Dynamic Link Libraries (DLLs) that have been loaded, and whether or not the PDB (Program DataBase) file containing debug symbol information was found. Normally, the PDB file for your application will be found, as it was here, but PDBs for run-time and system DLLs will not. Unless you plan to debug the system DLLs you don’t need their PDB files and should ignore these messages.
