Under 'About my Mac', there is no 'Manage' button in the Storage tab. How do I enable the Manage button? The version is MacBook Air Early 2015 with OS X El Captain (version 10.11.6). I need to clear the disk space as I'm having issue doing back-up of my iPhone to iTunes as it kept prompting insufficient disk space.
MacBook Air, OS X El Capitan (10.11.6)
If my memory is correct, the Manage Storage button was introduced with macOS Sierra (10.12).
One method of clearing disk space would be to look for large files and either delete them if you don't need them or move them to an external drive (and include the external drive in your backup routine).
The following applies to El Capitan and may help: OS X El Capitan: Increase disk space
The following may also help:
http://osxdaily.com/2016/02/06/mac-startup-disk-almost-full-message-fix/
Omni disk sweeper may also help identify files:
Under 'About my Mac', there is no 'Manage' button in the Storage tab. How do I enable the Manage button?
