How to debug a referenced dll (having pdb)

If you have a project reference, it should work immediately.

If it is a file (dll) reference, you need the debugging symbols (the "pdb" file) to be in the same folder as the dll. Check that your projects are generating debug symbols (project properties => Build => Advanced => Output / Debug Info = full); and if you have copied the dll, put the pdb with it.

You can also load symbols directly in the IDE if you don't want to copy any files, but it is more work.

The easiest option is to use project references!

Another point to keep in mind, be sure the referenced dlls are not installed in the GAC. After testing, I installed my dlls into the GAC to do system level testing. Later, when I had to debug my code again, I couldn't step into the referenced assemblies until I deleted them from the GAC.

I had the same issue. He is what I found:

1) make sure all projects are using the same Framework (this is crucial!)

2) in Tools/Options>Debugging>General make sure "Enable Just My Code (Managed Only) is NOT ticked

3) in Tools/Options>Debugging>Symbols clear any cached symbols, untick and delete all folder locations under the "Symbols file (.pdb) locations" listbox except the default "Microsoft Symbol Servers" but still untick it too. Also delete any static paths in the "Cache symbols in this directory" textbox. Click the "Empty Symbols Cache" button. Finally make sure the "Only specified modules" radio button is ticked.

4) in the Build/Configuration Manager menu for all projects make sure the configuration is in Debug mode.

Step 1: Go to Tools-->Option-->Debugging

Step 2: Uncheck Enable Just My Code

Step 3: Uncheck Require source file exactly match with original Version

Step 4: Uncheck Step over Properties and Operators

Step 5: Go to Project properties-->Debug

Step 6: Check Enable native code debugging