I have an issue when using SystemView and my J-Trace emulator.
I can run SystemView once after connecting and downloading my application, but after the first time, it cannot find the special SEGGER_RTT_CB structure when attempting to start a new (SystemView) trace.
Running the same application with my J-Link Ultra+ works fine with SystemView starting and stopping.
Any suggestions?

This is not a problem anymore, I don't believe. I think the problem stemmed from borrowing an emulator which may not have had the latest firmware on it. Consider this resolved.