To do that, click on the Apple icon, select About This Mac and go to the Storage tab. The first thing to do before you start deleting things is to check what type of files occupy the most of your storage space. The solution? Recover as much free space as you can! Check What Takes Up All the Space But if your Mac has a traditional HDD, then disk fragmentation will grind your nearly full drive to a halt. If you use an SSD, then you won’t get affected that much (although your RAM usage will skyrocket to compensate for the full disk). As soon as your SSD or HDD gets filled up to about 80%, your Mac will get a lot slower. If you think that a full hard drive has little to do with your Mac’s speed and performance, you’re wrong. How Does a Full Drive Affect Your Mac’s Performance? You could, of course, start paying for 50GB of iCloud storage for $0.99/month but we recommend that you free up space on your Mac by deleting stuff you don’t need first. Considering that movies in HD quality take up around 3GB on average, a MacBook Air’s 256GB SSD can fill up really quickly. Running low on disk space is perhaps the most common computer problem around the world, which got worsened by the Covid-19 lockdown - people started using their computers a lot more, downloading and saving more bulky content like movies. When you see it, you start wondering how you managed to fill your Mac’s SSD that quickly - it looked almost limitless when you first got the machine! It usually starts with the dreaded “Your disk is almost full” popup. How to Free Up Space on Mac: the Ultimate Guide

How to free up space on mac air