The installation log file is intended for debugging purposes and contains messages that may help resolve issues that arise in the field. During installation and maintenance the installer will create and log to an “Installer.log” file created in <Documents & Settings>\<Current User>\Local Settings\Temp\Mail Express. At the completion of the installation run, either due to success or failure, the installer will copy the final log to the <Installation Directory>\logs directory if it exists. Note that if the installer fails during an initial clean installation the <Installation Directory>\logs directory may not exist. In this case the final log file will be in <Documents & Settings>\<Current User>\Local Settings\Temp\Mail Express.
The installer will attempt to append to the existing log file on subsequent runs of the installer (e.g., if the user performs a “Reinstall”). It does this by copying any existing Installer.log file from the installation directory into the temp directory, writing to it during the install, and then copying it back to the <Installation Directory>\logs directory at the end.
You can write out the same log messages to another log file of your choosing using the /logfile=<Log file> command line switch to the installer.
The installer is capable of writing the same messages that go to the Main Installer Log (see above) using the Windows debug logging infrastructure. These messages may be viewed using a utility such as SysInternal’s DebugView application.