Visual Studio 2012 / C # breaks code execution, no breakpoint is set
I have a problem in Visual Studio 2012 / C # that is driving me crazy. I have a specific line of code in a C # file with a breakpoint missing. Every time this line needs to be executed, the debugger interrupts the execution of my code as the breakpoint was set. The only difference I noticed is an arrow on the left side indicating the current step. Usually this arrow is yellow (when a breakpoint is set). In my case, it is gray.
I searched for a solution but didn't find anything useful for this. I tried to remove all breakpoints, build project, rebuild project, clean project and it still appears.
Anyone have the same problems and found a solution?
normal arrow: 
arrow in my case: 
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This line of code is currently being executed, it calls something else, for example. internal code or internal .NET code and the exception happens there. You can see both arrows in the call stack window:
You may need to enable Show External Code.
If you don't see an exception dialog, you can usually show it like this:
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