On recent versions of D-RATS, the debug log is displayed by going to Help -> Show debug log.

 

If D-RATS is not starting or it crashed you will need to get the debug log manually.  Each time D-RATS is started it clears the debug log, so restarting after a crash (in order to access the log from within the program) will clear the information about the crash.

 

On Windows, go to Start -> Run and type %APPDATA%\D-RATS.  In the resulting window, save out the debug.log file and attach it to a bug or email.

 

On Linux and MacOS, the debug log will be in ~/.d-rats/debug.log.