I have installed osmc on my 27 inch screen running on a mac but when i boot up i only get a black screen

i have installed osmc on my rasbberry pi 3 but only get a black screen when i boot it up

You should read this post and think about what information to post.
At the moment we have no idea what is going on, and any suggestions would be pure surmise.
Derek

Does it work with another tv/pc monitor etc ? Tried a different HDMI cable ?