What a relief. I was experiencing exactly the same issue after the most recent update to Windows 10 today. I also noticed that besides this rubber band / outlining effect not working, the snap aperture was not visible. I also have a Surface Book i7 with 16 gig Ram with the on board intergrated graphics and Nvidia GPU. I run Turbocad 2016 Pro Platinum. I uninstalled and reinstalled, deleted default folder etc... to no avail.
After reading http://forums.turbocad.com/index.php/topic,22080.msg133008.html#msg133008
and this thread, I decided to try and see if I could force Turbocad to utilise the on board integrated graphics via the Nvidia Control Panel. After achieving this I restarted Turbocad and hey presto, the rubber banding/ outlining / preview / whatever you want to call it was back.
So 4 hours of messing about, I find that it is some form of graphics driver incompatibility causing a key feature of Turbocad to stop working. My disappointment with my top of the line Surface Book continues. Having the Nvidia graphics card for this laptop and its supposed compatibility with 3D cad packages was the reason for buying it, and now I am forced to stop it working with Turbocad.