You might have to wait until the process flushes its log buffer and writes to the log file. I know for the HTTP service you can manually flush the buffer and force it to write to file using this:
netsh http flush logbuffer
I'm looking around for something equivalent to that for the SMTP service.
Or, take a look at this from Steve Schofield's blog:
I was working on installing Windows
Server 2008 x64 edition. I discovered
the SMTP Service wasn't logging. SMTP
was working and emails were going out.
My install is 'custom' and installs
just the modules we needed. Turns
out, there is a small dependency on
the ODBC logging module so the SMTP
service logging would work. More
importantly iislog.dll. Here are the
instructions to fix and reproduce the
To correct it. I'm assuming you have
the SMTP Service already installed and
it's not logging.
1) Install ODBC Logging module (role
service in Server Manager)
2) Stop / Start the SMTP Service
3) Verify your SMTP service is
configured for logging. It's not on
4) Try a local telnet test (assuming
the telnet client is installed)
5) Look at your log folder.