Can't rotate viewport

For some reason, I can no longer rotate the viewport in any of my projects. I can move the viewport around, and zoom in/out, and switch from iso to perspective, but I cannot rotate the viewport. Very annoying.

I’m getting an error message every time I move my cursor over the viewport, as well:

transform.rotation assign attempt for 'SceneCamera' is not valid. Input rotation is { NaN, NaN, NaN, NaN }.
UnityEditor.DockArea:OnGUI()

Anybody know what might be going on? I recently upgraded to Pro, could that be affecting it?

Pro doesn’t have different behavior than Free; it’s the same program. I think I had this happen once…try resetting the panel layout by choosing the layout again in the drop-down menu, or at worst restart Unity.

[23289-screen+shot+2014-03-08+at+5.11.20+pm.png|23289]

I had this problem too. I found out the solution.

Do you see that “2D” button under the play button (black triangle) ?

Click on that to toggle back 3D viewport :smiley: