SOLUTION:
Go to your GW2 application. Right-click and choose “Show Package Contents”
Navigate Contents -> Resources -> transgaming -> c_drive -> GW2
Rename gw2.exe to oldgw2.exe
Rename gw2.tmp to gw2.exe.
Launch GW2.
The launcher will start and will begin the download. I’m downloading now.
Edit: The fix persists through multiple launches.
Taken from https://forum-en.gw2archive.eu/forum/support/bugs/Mac-client-broken-display
That worked fine for me! Thanks!!