Info-Mac

I have been using array sync very successfully on many occasions with a mac mini and two screens in a spanned arrangement. I updated the Mac mini OS X to Yosemite and now (coincidence or not?) array sync is only sending video to one of the screens. It looks as it should for that screen (i.e. it is half of the video file) but the other half does not show on the other screen (it just stays with the desktop image).
The other change to my set up is that I am using different screens as I am abroad at a fair. But the screens look as though they are connected correctly to the Mac mini - that is in the display & arrangement system preferences they are not mirrored and I can use them as expected - moving windows around the desktop etc. I have tried swapping the cables and that does not help either.
Any help would be very very gratefully received - the exhibition starts tomorrow and I am at a loss to know what to do.

Go to System Preferences and choose the Mission Control tab. From there, disable “Displays have separate spaces” and you should be good to go.

I'm also having trouble with video not showing up on all of my screens. I'm sending three videos out to three different projectors using a Macbook Pro w Yosemite ("Displays have seperate spaces" is disabled). When I use "Standard Mode" I only get video on two of my three screens; however when I try to span a video it uses all three projects--so I know the projector is communicating correctly with Arraysync. I've also verified that the video file used on the inactive screen is fine--it plays normally when I move it to other displays.

Any advice?

What happens in mirrored mode? Can you attach a screenshot of how your displays are arranged in System Preferences?

EDIT: Wait how are you driving three displays from a MacBook Pro? I hope it’s not with a TripleHead 2 Go