VS2010 Debugger --The source file is different from when the module was built

Error message:

The source file is different from when the module was built. Would you like the debugger to user it anyway?

 

When choose Yes, the breakpoint will be hit, detail information is:

 

"The breakpoint will not currently be hit. The source code is different from the original version."

right-click on the breakpoint in question, and you should see a Location item. On the resulting dialog you should see an override checkbox which will get rid of the message you're seeing when you hover over your breakpoints. Or you could go to Tools->Options->Debugging->General and uncheck the "Require source to exactly match..." option, which will turn off all checksum functionality in the debugger.

 

Solution:

Build->Configuration Manager

Check whether all project allows to build when the Configuration is Debug.