I had a similar issue when I updated my workstation to Windows 10. MY VAR helped me with the issue and it turned out that Keyshot 5 and Windows 10 had problems working together. After I updated Keyshot to Keyshot 6, the problem disappeared and everything works like it should now. The update is free when you have Solid Edge.
If you still have Keyshot 5, you can update to Keyshot 6 HERE