I'm interested to know about this. I am an old TT user of many years and have purchased an XT to see if it's better. I am running Big Sur on a brand new Macbook Pro and never have any issues with TT planning. BC seems to throw up lots of issues, such as I cant see detailed maps, only A roads, even the detail slide is as far to right as poss (Max). The preferences window seems to indicate I have a US version as it asks if I want to not use Interstates instead of Motorways (is there an EU version? It all seems so much harder to just set up and use compared to TT