High Sierra installation

[IfYoureHappyAndYouKnowIt]

I've been trying to install High Sierra on my MacAir but for some reason the installation is getting stuck and never finishing. Does anyone have any ideas? I've tried a number of times and have installed El Capitan successfully so the HS install should just run.

Is your air part of the machines that are allowed to install it ?

Sorry I only just saw your reply.

As far as I can see it should run on a MacAir. That said having Googled a bit quite a few people seem to have had problems installing it.