An installed checkbox is related to size classes is your size classes enabled for that storyboard
?
For Older Xcode, you can find this Use size classes
checkbox in the first tab of Attribute Inspector.
For XCode 8.0 and grater you can find the new option Use Trait Variations
checkbox in the first tab of Attribute Inspector.
see the screen shot:
Then & then you can see the Installed checkbox in the Attribute inspector.
Hope this will helps.