Legacy versions of mochaare not supportedondual monitor thunderbolt systems or systems with several thunderbolt ports in use. This was a known conflict with our FLEXlm license dependency and MAC Thunderbolt systems. This issue has been resolved in the latest version of mocha V4. Please make sure you have mocha V4.1.o or above installed on your machine in order to fix this issue. If you continue to have thunderbolt issues, please contact support. Please note: the legacy versions of mocha V3 and below are not supported on new Mac thunderbolt capable machines.If you have legacy software and are unable to upgrade to V4 at the moment, you should try unplugging all unnecessary thunderbolt ports, except one, as a workaround before activating or starting mocha. Currently, you can only have one thunderbolt port active for legacy mocha to activate and run properly. Usually users decide touse this single port for their monitor.