I have a VI that runs using a GPIB-ENET/100 to drive my instruments. During execution Labview sometimes locks up with or without an error. I cannot remember what the error says exactly right now. The GPIB-ENET/100 box has the Talk LED stuck on and it must be power cycled to recover. Also Labview must be closed using task manager as it is unresponsive to Windows Xp. I am using the Instrument Assistant for all of my GPIB communications. Some of them have several write and or query tasks in them. Is it possible that these commands in the Instrument Assistants are being executed too quickly? Is there a way to slow the commands down within the Instrument Assistants? All Instrument Assistants have GPIB code selected vs. VISA. The thing is, sometimes the VI runs straight through with no problems. Other times it happens pretty often. It is very intermittent. I believe I have enough Time To Wait VIs were it appeared to be necessary. Any ideas out there as to why these lock ups are happening?