"PDB does not match image" error in C# VS2010 project
I've been using a library in my code base for a while now, and I wanted to debug right into the library level. To do that, I downloaded the source code and included the project as an existing project into my C# solution. I then had my other projects reference that project instead of the downloaded .DLL.
Once the project was referenced instead of the DLL, I ran my solution through the debugger and tried to step into a function call that would have called into the external project, but it stepped right over it. While debugging, I opened up the "Modules" window and saw that the DLL's Symbol Status read "PDB does not match image", which is the likely cause of not being able to debug this project.
My question is simple, why does the PDB not match the image if my project is directly referencing the .csproj file as a reference? There should never be any ambiguity as to what version to run.
Answer
I've run into this issue before when I have another project open that also references the DLL and uses its debug info (PDB). Basically the other project puts a file lock on the PDB in the referenced project and when you compile or debug the referenced project, it quietly fails to generate an up-to-date PDB file.
If this is what is going on, make sure you have no other apps running or instances of VS open that reference your DLL, and then seek out and delete all copies of the PDB from beneath the BIN and OBJ folders, then recompile it.
I hope that helps.