In Photoshop CC I have no 'Extensions' menu under Window. I get Arrange > Workspace > 3D then everything else. I've searched and heard of it being greyed out but not missing entirely.
Extensions manager has been used properly to install my extensions, and I've manually checked everything is where it should be. I ran the manager as admin.
This is on a PC, W7 Pro 64BIT, CC is all up-to-date.
Moving this discussion to the Photoshop General Discussion forum.
What version are you running? I have 126.96.36.199 here.
I had a problem with the EM myself a while back, thatwas fixed with an update. Otherwise, I'd be inclined to remove and reinstall it. It's not a big app after all.
Photoshop tells me it's 14.2.1 (14.2.1 20140207.r.570 2014/02/07:23:00:00) x64
CC tells me it's up to date. I've tried reinstalling. I've also tried reinstalling on a blank admin account. Also tried disabling non-essential services.
Still no extensions menu.