I'm using Mackbook Pro 2016 13 inch. I recently changed settings of a live wallpaper app called iwall, which were settings for displaying live wallpaper on secondary monitor and change lockscreeen preview wallpaper. It worked well when I firstly set but after reboot my second monitor broken.
I can't describe it well in english, so i'll post my symptoms video here


In short, menu bar disappears and fullscreen windows on primary screen weirdly duplicated, they also appeared in second monitor and they kinda sync when i switch apps between fullscreen windows.
So basically, this problem happens not only on my secondary monitor, if i set my macbook pro's monitor as secondary monitor then it happens also in my macbook's monitor.
Also, this problem does not appears when i login to different user.


So i think it's problem of broken user preference or something with corrupted inner data caused by iwall app. it still happening after reverting iwall app settings to previous and even uninstall it. also i tried safe boot mode, still even it remains while in safe mode. I also tried reset the nvram and smc, didn't work either.

So my question is how to solve this? Is there any related inner system settings that i can revert?

1 Answer 1


You have Mission Control prefs set as 'Displays [do not] have Separate Spaces'
Check this box to fix.

enter image description here

  • Omg it was so buggy so i didn't doubted that setting caused this. why apple didn't even test their official settings? You made my day thank you and have a nice day!
    – Oh Won Sik
    Commented May 6, 2022 at 14:03
  • It's a fullscreen bug if anything, rather than a Spaces bug. Fullscreen was just not designed for multiple displays & spoils most of the things Spaces was good for (one more reason I never use fullscreen). Since its introduction Apple seem to have forgotten all about Spaces & haven't made one single improvement to it in years.
    – Tetsujin
    Commented May 6, 2022 at 14:21

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