I'm having the same problem. My sub vi is called by a larger shell vi, that was written in LV 6.1. It worked fine last week, this week, its a different story. What could possibly have changed over the weekend. I'm going to contact my IT guy to see if he changed our network settings, but in the meantime do you know of any possible reason why one out of many sub vi's called by my main menu vi has now decided not to work.