I have software (program #1)that I have compiled under both 5.0 and 6.0 It functions on the hardware under a Keil 5.0 compile. It will build and load under Keil 6.20c but it will not run correctly. I have another program (program #2) that I have compiled under both 5.0 and 6.0. It will load and run on the same hardware as program #1. These programs are running very similar code. Program #1 WILL run if compiled under Keil 5.0. Does anyone have any ideas??