Hi Robert,
The white X means there is a discontinuity in the data. For example, if you are using LoggerStopMode and you run your program for a bit and then halt the target, you get the data in the LoggerStopMode buffer displayed in System Analyzer. Then suppose you run again, for sufficiently long so that the buffer is overwritten. Now when you halt the target, there will be gaps between the newest Log event in the first buffer and the oldest Log event in the second buffer. In that case, you should see the data loss in System Analyzer.
Best regards,
Janet