wuser32.pdb not included message during debug on Visual Studio Express 2013

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Windows

1. plain C program Windows 7 ultimate
2. Debug/Start debugging (F5)
3. I have a breakpoint at this instruction: return(CallNextHookEx(NULL, nCode, wParam, lParam));
4. it stops at that breakpoint
5. I step over to next instruction which is a right brace '}' closing a Switch/Case
6. it moves to the right brace
7. now,whether I 'step in', 'step over', or 'step out' it displays a big window saying as follows:

wuser32.pdb not included
Symbol loading for user32.dll was skipped because it is not specified in the included modules list.

How do I avoid this, please?
All I want it to do is continue executing the target program.

With thanks!
/nick