I want to see what's going on backstage. Where does MiKTeX write the trace messages?
MiKTeX programs log their actions into the DebugView window, if you specify suitable trace options.
How do I use the DebugView window?
First of all, you will need the DebugView utilitt, which is a part of the Windows Sysinternals suite. To download. To download DebugView, visit the Windows Sysinternals page.
How do I set trace options?
Set the environment variable
will trace all errors and file accesses. For more information, read the section Trace Streams in the MiKTeX manual.