Hello Harriette,
Your BimX desktop viewer is a software which seems to be updated like an iOS or Android App.
BimX application is developed in parallel with the Archicad application.
Also you need to consider your Archicad version to know if your Bimx application can read your Bimx export.
You have to understand that Bimx was born on iOS more the 6 years ago because it was and is always the best device to develop all BimX pro is able to become. that's why BimX is available before on iOs and then on the other device which include android, but macOS and windows too.
Finally when you see you BimX on a macOS or windows you only see a part of your BimX file. I invite you to open your bimx file on a smartphone or a tablet (windows surface pro isn't a tablet) to take all the best of your project.
Have a great day,
Christophe - FRANCEArchicad Designer and Teacher
Archicad 15 to 27 FRA FULL
OS 11.6 Big Sur - MacBook Pro 2017 - 16Go RAM
"Quality is never an accident ; it's always the result of an intelligent effort" John Ruskin