It seems that I have having to delete and redownload Arduino every day. I have only just started using it so I'm not too sure what the issue is. If I download a fresh version I can use it all day with no problems at all but the next day when I come to use it it just won't open. If I delete that version and redownload it it works fine.
I am running macOS - High Sierra. It happens with all different versions of Ardunio. It's terribly frustrating as I assume its a setting in my mac but I have no idea how to rectify the issue.