SketchUp causes external hard drive to spin up making Windows freeze for a few seconds

I have an external hard drive connected to my PC that turns on when I boot up – it’s a backup drive.

It doesn’t actually need to be on all the time – so a solution to my problem would be to only turn it on when I do backups.

If I have SketchUp open and I have been away from SketchUp for a while – working in Layout, researching on the web – when I come back to SketchUp the external hard drive spins up and while it is doing so Windows freezes.

Any ideas?