I recently installed ArcMap 10.4 on my Mac (OS X 10.11.3) using Parallel.
When I opened Identify Tool, the window opened beyond the screen, and I cannot reduce the size, as the 'minimize' or 'restore' icon is not visible because the window had expanded too far.
I tried three different things: a) adjusting screen resolution, b) Zooming, c) script editor to tell ArcMap to keep window in a certain size etc. but the problem still remains. I restarted the program, but since my piece of work was already saved when closing the program last time, the Identify Tool window pops up (beyond the screen) every time I try to start the program, and I cannot go further unless I am able to close the identify tool window.
(I had similar problem with Attribute Table - when I expanded it, it displayed beyond the screen, and could not close/minimize. For this, adjusting screen resolution helped.)