What does it mean the information message "You have to re-pair device..."?
The Windows manages Bluetooth device (vs all the other platforms). Unfortunately Windows is designed to handle Bluetooth connections at the operating system level, this gives app developers much less access to how they are handled and causes a lot of headaches.
Unfortunately, we have found the critical bug in Windows 10 about Bluetooth connectivity and we are waiting for fix by Microsoft. In meantime you have to re-pair all previous connected Bluetooth trainers and sensors in Windows Bluetooth manager and connect in VT Desktop again. We are sorry for problem, but it's temporarily solution hopefully. Once Windows 10 will be updated, we will inform you asap.
Instead of pairing them each time, the better solution would be to use the BlueGiga Bluetooth adapter instead of the native Bluetooth in windows. The use of this adapter avoids all current Bluetooth issues by allowing the pairing of devices to be handled in VT (like ANT+) and will remain paired properly when you close and reopen VT.
There are some online resources for this Bluetooth adapter.