How to disable Instant Run for Android Studio 3.0
Instant Run is not a feature of Android Studio 3.5 (and later) any more and so cannot be disabled. In case you find an old guide recommending to disable it, you can ignore this instruction. See here 1 and here 2.
Just make sure you go to Android Studio -> Preferences instead of File -> Other settings -> default settings. Instant run should be there.
Go to Android Studio Settings or Preferences (for MAC)
-> Build,Execution,Deployment
-> Instant Run.
Then deselect the "Enable Instant Run" checkbox at the top.
Linux Screenshot:
Windows Screenshot:
For Mac go to Help in MenuBar and type 'preferences' or, go to 'Android Studio -> Preferences' in MenuBar
Mac ScreenShot