I just wanted to share with you about the progress on this issue. I tried Sean's approach, the .dll did press the alt key but also closed my application, therefore, and it was not practical.
I further drilled down and found out a subvi that caused the CPU 100%. Further isolating each part of the code in the subvi, I finally found out that it was a numeric control that caused the problem. If the control had a value of Inf (infinity) and I configured the control with representation of DBL, the CPU went 100%. I could configure the control with SGL or EXT representation, the CPU problem went away. Or I eliminated the control from getting the Inf value and kept the DBL representation, the CPU problem went away also. However, after I built the application and ran the executable, the CPU 100% came back again, I had to use the alt key to let it go normal. Hope this will help NI troubleshoot the problems. Thanks, Yurong
