Thank you mate for posting that, I was haveing the same problem and unfortunatly rang tech support for rescue who were as helpfull as a choclete fire guard.
Well its Friday and after 2-3 days of all working great we are now back to square one, rescue works fine on my PC Win 10 Pro, it works fine on my older G5 Apple Mac, and is totally useless on my Apple Book Pro.
No new updates on Laptop, rescue starts, I can see clients machines, I can enter their user names and passwords, then it just freezers once I try to login to clients machines.
So as long as I site in my office for the rest of my life and don't upgrade any of my machines all works.
Is anyone having better luck than me with this problem.
@gwpd Specifically which Rescue version are you running on the problem Mac? If you're not running the Mac beta testing version, I will post this as soon as it becomes publicly available to all customers. Thanks for your patience.