The Avanti log file is enabled by default.  This file logs the emulator startup, shutdown, runtime, and error messages.  6 log files are retained by default. A version number appended to each log file name denotes past log files.  A fresh log file is created each time the emulator is launched.

Current Log:                .log
Previous Log:                .log;-1
  ...
Oldest Retained Log:        .log;-5