Hi there.
I’ve just got a new laptop setup so I can continue work while in hospital for 3 bloomin months, all has been going really well, but I’ve just noticed my Alt+Click isn’t working.
I’m using files and user preferences from my desktop so I can’t think of any problem settings, and the Alt key works in every other way. So does the click for that matter.
Windows. Blender 2.78. MSI GT73 Laptop.
Any ideas?
Thanks.
Just in case anyone else comes across this problem, try turning off Emulate 3 button mouse. Fixed the problem in this case.
Tclancey, Thanks for posting your solution. I didn’t respond because I had nothing to offer. Maybe next time I’ll have an idea at least. 
Not your problem it seems… But some operating systems capture use of the alt key for the desktop, which I happen to find a bit boneheaded and annoying. (Causes problems with defaults in a whole slew of software. So that decision wasn’t well thought out.)
Most Linux distros are that way… (So for anyone looking, there’s a fix in that case too.)
If you’re in Linux, you can use dconfig, click on the upper left menu for find, type in “modifier”, and keep hitting next until you get “mouse button modifier”. (Not sure the exact, but it’s something like that. Path for that also changes a bit depending on desktop manager or distro anyways. Thus going through the find process.) Change the mouse button modifier from <Alt> to <Super>. Now that frees up the Alt key to work in software as it should. But you still have access to desktop mouse actions by holding down the Win (a.k.a. Super) key.