How do I set breakpoints and debug engine plugins?

I am trying to use breakpoints in an existing engine plugin.

I built the entire engine from source in VS 2013 (Debug Editor). The plugin binaries folder has both the dll and pdb file. I launch from the editor with startup as UE4 with command line options of SampleGame -debug and startup as samplegame with command line option of -debug.

For both situations, breakpoints in the source for the plugin show the hollow red circle error, saying “no symbols are loaded for this document”.

In the startup log, for all plugins, it says " Cannot find or open the PDB file".

I tried running -game as well, but hit the same results.

Previously I remember debugging plugins, but I do not recall how.

I’m interested as well.