How to Optimise storage in macOS
1 Check your storage
From the Apple menu, choose About This Mac. Click the Storage tab to view a bar graph that details what file types are eating up your Mac’s storage. Place the pointer over each coloured segment to view the type and space used.
2 View recommendations
Click the Manage button to open the System Information app’s Storage Management window. By default, this will open with Recommendations selected in the sidebar, outlining several ways you can reclaim storage space.
3 Watched videos
If you download films/TV shows in iTunes, click the button next to Optimise Storage. You may then be presented with another suggestion: to download only recent email attachments. Tick only the changes you want to make, then confirm.
4 Take out the trash
If you’ve a habit of chucking stuff in the Trash and never emptying it, click Turn On next to Empty Trash Automatically. Now any items in the Trash for more than 30 days will be deleted without you lifting a finger.
5 Delete big files
Click Review Files (or Documents in the sidebar) to see particularly large files residing on your Mac. Select one or more and click Delete to remove the selection from your computer. Be mindful that there’s no option to undo.
6 Browse files
Select File Browser and you’ll see something like column view in Finder. Folders display how much space they are taking up and are sorted by size. Use this to find and remove large folders rather than just large files.