VR Preview not working with SteamVR in new version

Hi!
I got a HTC Vive and tested it with some games and with a project in version 4.11.2
When i make a copy of that project in 4.13, SteamVR says that compositor isn’t in fullscreen and when i click VR Preview, it opens on a new window in the background (but it don’t change the state of the hmd), so i tried alt+tab, and the hmd goes red. Then i try alt+tab again, and the hmd shows some part of the game in one eye and some other on the other.
So i tried creating a new VR Template project, and still get the same error.
OS is Windows 10. Graphic card is a NVIDIA Geforce GTX 960M.
I already tried updating drivers and clicking in the SteamVR message, with no luck.
How can i resolve this?
Sorry for my poor english and thanks in advance.