It is related to the checksums which is used to ensure that you are stepping in matching source. You could disable it like this
找到Tools –> Options –> Debugging –> General，取消勾选“Require source files to exactly match the original version.”
调试报“The source file is different from when the module was built.”问题的解决
原文：http://www.cnblogs.com/x-poior/p/5568554.html