Way too often than we would like, we encounter this annoying error. And the most commonly used method of resolution is to manually resolve this issue by specifying a path to the pdb file as described below:
Open the Modules window
Debug Menu > Windows > Modules
In Modules window, locate the offending dll.
Manually locate the pdb file associated with the dll.
I have been using the above method, until recently I’ve discovered that, the above method isn’t actually the best way or approach to this issue. The best approach is to correct the Debug Info setting in your build settings for the offending project.
Within each project’s build settings, there’s a setting which controls whether a pdb file should be generated in the temporary folder of your application under the .NET framework folder or not. It is also worth noting that; Visual Studio uses this pdb file located in the temporary folder for debugging – not the pdb file in your project’s bin folder.
Go to the Build settings of the offending project.
Scroll right down to the “Advanced” button.
Make sure “Debug Info” NOT set to “none”.