Fullscreen not working after upgrade; OSX crashes

OS X can be installed over the same version or earlier version of OS X, without removing your data. You don’t need to remove or disable the existing system first.

1. Start up from OS X Recovery by holding Command-R immediately after turning on or restarting your Mac. Release the keys when you see the Apple logo. Startup is complete when you see the OS X Utilities window.
   
2. If you do want to erase your disk before reinstalling OS X, open Disk Utility from the OS X Utilities window, then use Disk Utility to erase the disk. Quit Disk Utility when done.
   Erasing the disk isn't necessary unless you're transferring your Mac to a new owner, partitioning your disk for use with Boot Camp, or attempting to resolve an issue that Disk Utility can't repair.
   
3. Choose Reinstall OS X from the OS X Utilities window, then follow the onscreen instructions.
   This installs the latest version of OS X that was previously installed on your Mac.

I also have this problem and have been working with Apple support to try to resolve it. For me it happens whenever:

• I try to take an app to full-screen mode
• I try to animate between Desktop Spaces using the mouse (two-finger swipe), trackpad, keyboard commands, or anything else that causes the Desktop Space to switch.
• I watch a video in full-screen mode

I think the unifying thing here is the automatic switching to a different Desktop Space, including for full-screen. Interestingly, if I navigate Desktop Spaces manually, usuing Mission Control, I'm successful in switching.

Of note, this is only affecting my account. I created a "test" account and everything works fine. Apple thinks it's something that's loading during my unique login and we're working on isolating the problem.

You may want to try the Desktop Spaces movement on your computer. If you have the same problem, we may have the same issue. If (when) I get a resolution from Apple, I will post here. BTW, you may want to create a "test" account and try going to full-screen mode with an app, and navigating spaces. If it works, you've isolated the problem to some idiosyncracy in your account.

You may be able to Safe Boot and have things work normally, though sluggishly. I was able to do this and convert any full-screen apps to regular mode, then quit them. They then work normally during a regular boot. Though I still haven't solved the full-screen crash problem, at least I'm able to use my Mac.

I posted a similar response on this thread---sierra full screen bug---which appears to describe a similar problem.

BTW, I've already performed the reset SMC, NVRAM, and PRAM, as well as numerous other "system" fixes, without result. If I get a solution from Apple (we're supposed to talk again on Monday), I will post it.

This is not a solution but a walk around, press the option key while clicking the green button, it will work like in the past allowing you to go max size available, at least it does not crash the system...

I have the same problem, and still waiting for a solution...

Thanks. I actually use Moom, which is a great window management program, so I can control the size of the windows pretty easily. I've also been manually switching Spaces with Mission Control. However, full screen viewing of YouTube videos, and viewing iTunes videos doesn't work because it requires the creation of a new space and the animation to it. It's that animation that appears to be the problem.

When I get a fix, I will post it and, hopefully, it will help you and others. I've identified at least five threads in the Discussion Groups on this topic.

I'm glad the issue was resolved for you, and I'm certain something similar will be the solution for others, including myself. However, I don't have an Razer products on my Mac.

I have the same issue and it is also happening on my iPhone after upgrading to ios10.

I also have this issue whereby attempting to enlarge any program to full screen causes my laptop to reset back to the initial user login screen.

I have also re-installed Sierra from the recover drive on boot -up but again with exactly the same results.

In a discussion with an Apple tech online I was told to erase my data and perform a fresh install of Sierra, basically onto a blank hard drive - well how do I get all my original data back onto the new installation of Sierra ? - I was also told that re-installing my data from a Time Machine backup would cause similar issues as if I was installing Sierra over a non-erased drive??

So, I'm a bit clueless now on where to go with this - other than, overnight I let my Air recover to its previous fully functional version of El Capitan !

Looking forward to sorting this out properly !!

Have you tried setting up a test account, a new administrative account named "test," with password "test?" I recommend you try that first, then see if the problem persists. If it doesn't, then the problem is very likely isolated to your account. When I set up the account, it worked without difficulty or problem.

I had also tried a reinstall of Sierra, without resolution.

I got a call from Apple Engineering (not Support) yesterday about the logs I submitted. I wasn't home but hope to speak to them in the next day or two.

I wouldn't do anything drastic yet, unless the problem persists in your test account.

There is a reasonably active thread on this topic here: Mac Os Sierra keep logging out !!

I am having this same issue and also have Razer Synapse installed. All you did was update the program?

Not only did Option key work, but after I did that, full screen and iTunes visualizer worked fine without subsequent use of Option key. Interesting...

Issue is not solved! I don't have Razer Synapse (don't know what it is, searched for it, didn't find it). My systems goes back to login screen with any application (including Apple's like preview) that go to full screen. Can't show pictures, can't view videos. Upgraded to Sierra was a big mistake.

I have this issue with 10.12.1 and the latest Razer drivers as of November 5, 2016. Also gave me difficulty with rebooting the computer.

I still have this issue. I tested full-screen video in Chrome, Safari, and iTunes (with a movie). They all cause a "crash" meaning I am logged out. I am on a Macbook Pro with a 27" Thunderbolt Display.

Wait...

so how do I fix razer synapse?