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I have a MacBook Pro (Retina, 15-inch, Mid 2014) running macOS Sierra, the Mac started to be slow due to storage.
When I've checked my storage I was shocked, from 250 GB I have, 180 GB was allocated to the System it self!
I've checked my friends storage and found that the System is only 30 GB!
How can I manage this and why do I have that much storage allocated to the System?