Canvas elements missing on certain computers

I've recently updated to unity 5.3.1f1 and just started having this issue...

I have Canvas GUI elements that display a players score, health, dPad and buttons (for touch screen and eventually mobile devices). When I build out the project for the PC and run the executable, everything works great. I can use keyboard or my canvas controls to control the character and it's all working as implemented.

However, when I send the project and _Data folder to other users the chances of the Canvas elements showing up and hit-and-miss. So far they show up on 2 out of the 3 PC users I've sent the project to, however they never work on Macs w/ a Windows partition. So I made a Mac build for the Mac users to see if it would fix the issue, but it has not.

I find this very strange because if it were a coding/setting issue, it shouldn't show up at all on any computer, but it's only having this problem on Macs (so far) even with a Mac specific build. Am I missing something, or is there a bug I am not aware of in 5.3.1f1.