Build 15002, Surface Pro 3 with Surface Dock won't finish booting up

After 15002 installed on my SP3 with Surface Dock, now when the machine boots up all goes well, I can login, and it begins to draw the desktop, then stops. I can move the mouse and play with desktop icons, but if I move down to the Start button or task bar all i get is a spinning, busy pointer.

I've left it in this state overnight with no progress, but if I disconnect the docking station it immediately proceeds and completes the boot sequence, and I can plug the docking station back in and all is well going forward.

This isn't a show-stopper, but it's annoying. I have two external monitors connected to the Dock, fyi.

For reference, version 15007 installed last night and the problem is now gone.