Tag all files required by OS My hard drive is close to full, so I am trying to delete old and unused files. I am worried that I may delete files that the operating system needs, but I don't recognize. Is there a way to tag all of the files that are required by the system, so I can ignore them while cleaning up storage? I'm thinking in terms of a program or some code you may have made/come across.

Currently using MacOS Sierra version 10.12.4
macOS Sierra comes with SIP (System Integrity Protection) which protects all important files from getting removed. So an additional tagging is not really necessary. 

In finding disk space hogs some of the answers to How can I figure out what&#39;s slowly eating my HD space? might be helpful.