My 2012 mini usually outputs to two monitors - one for work and one for making work less boring with Netflix. One's connected via the HDMI output and the other from mini DisplayPort through an HDMI adaptor. The one connected to the HDMI out is mostly not working now. System only sees one screen, monitor sees no incoming signal. Sometimes it works after a reboot but then at an arbitrary point it goes off again. I've switched monitors and cables in every combination and narrowed it down to either the HDMI port itself or something in the OS since installing Sierra. A blank copy of Sierra on an external drive makes no difference though. So is there any other way of having my two screens running again? I was hoping a mini DisplayPort to 2x independent HDMI splitter adaptor existed but it doesn't seem to; only for mirroring or only for Windows machines.