Signal choppy from VISA, except when NI I/O trace running in background

Dear Folks,

Strange issue, have been trying everything that i Know.. but unable to crack it. 

Simple Serial port data ( from 1 sensor and 1 encoder) - 

RS232- to -USB converter and reading in my program. (LV 8.5)

Works fine in my other computer with windows 10

in my customers system (windows 8), the signal is choppy esp from encoder.'I tried varying all possible parameters but to no avail

I ran NI I/O trace in the background.. an the signal is no more choppy!!

Trying to find out how I can run the app in this system without Trace in the background all the time... 

Any help is appreciated.. Atached are the pic of the block diagram and that of the signal, with and without trace..

Thanks,

Palch