From Ssl-wiki

Windows

First, click on Start, then select the Control Panel

In Control Panel, switch to Classic View from the upper left...

then, click on Folder Options

in Folder Options, click on the View Tab, then check the box that says Show hidden files and folders...

Click Apply then click OK. And that is it. Now you will be able to see and access the hidden .ScratchLIVE folder on the root of your external drive(s). Hidden folders will look semi-transparent...

Macs

For Macs, you can't really show hidden files/folders, at least not without doing some Terminal Commands. That's complicated, and there's a much simpler way. First, click on Go at the top of the screen in the Toolbar, then select Go To Folder...

On the next screen, type in /name of external drive/.ScratchLIVE. In the example, the external drive's name is EXTERNAL. Replace with the name of your external drive. Don't forget the period before ScratchLIVE.

Select Go, and that's it. You should now be in the hidden .ScratchLIVE folder. You can now copy and make a backup of your crate files, transfer crates from one drive to another, etc.