a matching symbol file was not found in this folder

Question

One of the things I've ran into with was because debug was off on the project referenced where the code lives. In my case, I made a new configuration called "Developer" and by default debug was turned off.

1. Right click the project in question
2. Properties
3. Build
4. Advanced (right bottom corner)
5. Set Debug Info to full
6. Recompile

I had the same problem as @DmainEvent. Apparently the dll that I was using was not the same version as the pdb that I had just compiled, so I got the error message.

If you have this problem, try using the dll and pdb from the same compilation run.

The error I got was "a matching symbol file was not found in this folder" in the Debug => Modules window even after both the DLL and PDB were available and built together, so I was unable to debug into the target DLL referenced by my main project.

Posting this here in case it helps someone browsing with "Mixed Platform" build for target DLL. I did two things to get past this:

1. In the solution using the target DLL, Uncheck "Just My Code" in Tools => Options => Debugging => General => Enable Just My Code (JMC).

2. Check "Enable native code debugging" in target DLL solution in relevant Project Properties => Debug.

I tried all the possible solutions, finally it worked when I disabled the option Enable native code debugging under the Debugger engines of Properties > Debug.