Has anybody got this to work on a Mac? Octipi won't load and the screen is solid white blocks, no wording.

Are you able to SSH into the Pi to see if it is connected to the network correctly? Are you using the IP address or octopi.local hostname?

Octopi on first boot can take several minutes to load.

LCD contrast (just added to the instructions):

https://makertech-3d.dozuki.com/Guide/Stage+01:+Base/50?lang=en#s792