If after installing V5.1SP1 NI MAX stops working you may reinstall the NI VISA for NI MAX to work. However, the TLA Application will then no longer see any modules unless you put a copy of the TekVISA from C:\VXIpnp\WINNT\TekVISA\Bin\Visa32.dll into C:\Program Files\TLA 700\System to guarantee the TLA Application will use its VISA instead of the NI VISA.