Trace: No Synchronization


I am using uVision V5.31 with a ULINKPro on an STM32F437 target.  I am using the Trace facility and outputting to the "Debug (printf) Viewer" window.

The Trace config is168MHz core clock (matches my target) and "Use Core Clock" checked.  When I start my code I get "Trace: Running ..." in the bottom status bar and trace output in the Debug (printf) Viewer - everything is OK.

However, if I reset the target via the uVision RST icon. I then get "Trace: No Synchronization" in the bottom status bar and no trace output.  If I then stop the code using the X icon and resume via F5 I then get the "Trace: Running ..." message and trace output resumes.

Any ideas how to fix this.  I remember it working OK in older versions of uVision and have lived with this problem for a while now.