So it seems that last night every file on the iMac I installed Mojave on was deleted. Anything not in iCloud is now gone. Weirdly all of the apps are still there, and all but every single file, photo, document, basically everything except the apps are now gone. I am not complaining because of course I made a back up, and I know this is a beta. Just giving a heads up to others that don't heed the cautions.