Attempt go to Tools->Options->Debugging->Symbols and choose checkbox "Microsoft Symbol Servers", Visual Studio will download PDBs automatically.
No problem. You're running your code under the debugger, and the debugger is saying you that it doesn't have debugging information for the system libraries.
In case you truly require that (generally for stack traces), you can download it from Microsoft's symbol servers, however for now you don't require to worry.
PDB files are coupled files bearing symbols of modules to be employed at the time of debugging. They are originated for your sources during the debug build process. However there might be no such files for external modules like system DLLs.
The messages you view in the debug output window are only informational and can be ignored.
In case you truly want these symbol files, see "Microsoft public symbol servers" at Specify Symbol (.pdb) and Source Files in the Visual Studio Debugger.
Further, for the Microsoft dlls (like msvcr dlls), you might require to link to the Microsft Symbol server. Read more about it here : Debugging with Symbols (Windows)
Employing a Symbol Server - Windows 10 hardware dev
Hence originally the system requires to know a location where it can download the symbols from the MS server as and when nrcessary (like symbol would be downloaded on require basis, not only for all dlls.) and the debugger reqyires to know this location so that while debugging, it can collect the symbols for MS dlls. this is how i remember it used to be . expect its same still )
These are not error messages - they are informational messages from the Visual Studio debugger listing the several executables and Dynamic Link Libraries (DLLs) that have been loaded, and whether or not the PDB (Program DataBase) file bearing debug symbol information was constructed. Usually, the PDB file for your application will be constructed, as it was here, however PDBs for run-time and system DLLs will not. If not you plan to debug the system DLLs you don't require their PDB files and must ignore these messages.
You may further see a message corresponding to:
The program ' Project01.exe' has exited with code 0 (0x0).
This notify that the program ran to completion and exited - here with conquest status of zero. In case you see this message instantly following the "Loaded" messages above, without having the program interrupt into the debugger, you will want to place a breakpoint at the first executable line in the program and then run it again. For C++ applications this is generally not required, however it is necessary for Fortran applications.