I am doing development with IAR EWARM, Segger JLink and an MK20. Was building up my environment for the new board. Libraries for MFS, Shell etc. I am now experiencing debugging issues. After programming has finished and execution begins, the LED on the JLINK flashes red (and green), execution is slow and it never makes it out of the start up code. If I load another project I don't have this issue. Has anyone seen this before and know what it might be. It has me stumped.