When you select the On Startup logging trigger, a Duration field appears. The default value is zero seconds (perhaps not a great default). This effectively means the log file never logs. Try setting this value to a larger number. You can even just use Inf if you don't want a limited logging duration. In that case it will log as long as the profile runs. The other limiter is the File Size Limit field. You can also set that to Inf if you don't want to limit the log file by its size.
Jarrod S.
National Instruments