How To Figure Out What Is Taking Up Space On Your Mac

Hi, this is Gary with MacMost.com. I'm going to show you how to find out what's taking up space on your hard drive without having to buy any third party apps.

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So on forums all over the internet I see Mac users asking how they can figure out what's taking up space on their hard drive and people answering with third party apps that you have to buy and install to figure it out. You don't need any of that. It's pretty easy to figure out what's taking up space on your hard drive by just using the Finder.

Let's start off by making sure we're in the Finder. Once we're there let's create a new Finder window. Now basically we're playing detective. We want to start at the top and start looking down at all the folders on our drive. We're going to use Go and Computer. This takes you to the top level. You can see I've got a couple of external drives but the drive I'm interested in is my main internal drive called Macintosh HD. I'll go into that and I'll see the main folders there. You're always going to see Applications, Library, System, and Users. Now from this point we want to pay attention to what's taking up space.

So we're going to switch to List View. I'm going to click this button here and to go to List View. Now I've got columns here. I can adjust the columns to move them around. I want to see the Size column. That's the one I'm mostly interested in. So make sure that's within view. You're going to see these little dashes here. It's not going to calculate the size of folders. That's pretty hard to do because It has got to look at every file in that folder, figure out the file size, and add them all up. Folders like Applications and System have tons of files in them. But you can force it to give you a size here by going to View, Show View Options, note this is Command J.

Here there is an option called Calculate All Sizes. We're going to check that. Then we're going to wait for it to replace these dashes with actual numbers. Give it a few minutes to do that. For me it took a few minutes for the Applications' folder size to appear and a few minutes after that for the Users' folder to appear. So Applications, of course, is where all your apps are stored and it's always going to be pretty big. Your Library folder and your System folder together make up the system. Most of the big files you're going to find in the Library folder. The System folder itself should never get too big. That's just the size of the System. Users is where all of your documents and data files are kept. If you have multiple users on that Mac they are all going to be in there.

So let's start by investigating the Applications folder. We don't need to double click it and open it up to see what's in there because in List View we can click on the Reveal triangle here to the left and it will open up and we can see all of the different files in there. Now if we click on Size it's going to sort everything by size. See the Users folder jumps to the top. The Applications folder is next and things inside the Applications folder are going to be sorted. So you can see I've got Xcode beta in there taking up a lot of space. Xcode is taking up a lot of space and on down. So I can ignore the small apps further down and pay attention to the big ones. Maybe there's an app in here that you can uninstall that's taking up a lot of space.

We can close that and then we can look at the Library folder. Likewise in the Library folder you're going to probably find Application Support at the top. You can open that up as well and see what's taking up a lot of space in there. So here I've got Audio apps, Logic and GarageBand taking up a lot of space. I can look inside them and see some of the things in there. You can go further on down. So you can see Applications that you may be able to uninstall to get back space in your Library folder. Also in the Audio file I'll find more files supporting GarageBand specifically taking up a lot of space.

So it's just a matter of looking through all of the things inside your Library folder and seeing what's taking up a lot fo space. If you don't recognize what it is maybe do a search for it to find out what this folder is for. Then you can make a decision from there whether or not you need it.

Now your Users folder may be the largest user of space as it is for me. If I open it up I can see all the users on this machine. So that's my main user account. This is the user account I use to make videos and I have a few other demo accounts. This account here, the one I'm using, is taking up a decent amount of space. I can look inside that to figure out what's using a lot there. I can see under Movies I've got quite a bit. I've got a FinalCut bundle in there. So a Final Cut library that's taking up most of it. Then I can look in Pictures and see a decent amount of space being used for my photos library and that's how much is being used for music, etc. You may find something like a ton of stuff in your Downloads folder which solves the mystery. Now you just need to empty your Downloads folder of things you no longer need.

Now notice something is missing here. 70 GB for this user folder. Then I've got this one that's less than 20 GB and another that's 3 and then everything is less than a GB. How can that add up to 70. It turns out that there's a hidden folder inside the User folder that's probably using a lot of space. That's the Library folder. Yes, we have this Library folder here. That's at the System level. That's the System Library folder. Inside of a User folder we've got another Library folder in each user's account. So in this case, in the MacMost account folder here, I'll double click it to go in it, you won't see that library folder. 

You can get to it by using Go holding the Option key down and go into library. But I don't actually want to see it here in the list. So I'm going to use that Command J again to bring up this list here. In addition to Calculate All Sizes I now have Show Library Folder. I'm going to use that and now Library appears. Let me adjust these columns here. I can see, sure enough, that accounts for all of the extra space.  

I can go through this Library folder just like I went through the System Library folder. Open it up and see what's inside.  Let me Sort by Size here. I can see Application Support is the majority of it. I can open up Application Support I can see  MobileSync is using a lot. Now MobileSync actually contains my backups for my iPhones. If you want to get rid of these iOS backups you go, in Mojave, go to iTunes, iTunes Preferences, then you click on Devices. Here are those backups, right there. So you can Delete them. Of course you may not want to delete them because they're useful as backups.

Figuring out what's taking up space is only the first step. Now you've got to do something to clear out space. If there are documents in your User folder that you no longer need you may want to buy an external hard drive, archive those files to that drive, and get rid of them off your regular drive to clear space. If they're applications you want to uninstall them. Make sure you uninstall them properly which means using the official uninstaller provided by the developer or instructions on their site. If you've got the app in the App Mac Store use Launchpad to remove the app. 

If they are items say in the System or User Library folder you want to be careful. Deleting things from there can cause trouble. Can make apps stop working or even the system itself stop working. So you want to do some research. Look up that item. Do a search online to figure out what that folder is for and really know what you're doing before you remove items from your Library folder. 

A lot of times you actually go into an app to remove things. For instance FinalCut Pro has the ability to cleanup its own files inside of FinalCut. So you want to do that there and not mess around with the files directly. Cleaning out cache files is usually counterproductive as they usually speed up using your Mac. For instance the Browser cache files make it faster to browse the internet. Clearing those out may temporarily give you space back but then it's just going to fill up again and until it does that means you're going to be redownloading those files slowing down your internet browsing.

Sometimes there's not much you can do. The apps that you've got and the documents you're storing on your hard drive are just taking up a lot of space. You may need to make some tough calls. Uninstall some applications you're not using as often, use iCloud Drive set to Optimize so that maybe some of your older files aren't going to take up space, and the next time you buy a new Mac make sure you get a larger hard drive.