How do I fix an “Invalid license data. Reinstall is required.” error in Visual C# 2010 Express?

I am using Visual Studio 2013 and I have the same issue but it occurs when I try to open a solution that was made using Visual Studio 2010.

The solution for me is to open the solution file (.sln), using notepad and change this line:

[# Visual Studio 2010]

to this:

[# Visual Studio 2013]