If your Mac is running out of disk space or you’ve seen that scary “startup disk is full” message, you know that freeing up storage space can be frustrating. To deal with this problem, many people resort to external drives and continually juggle their files between drives.
Although you can manually track the available storage space, we will show you how to check the disk space on a Mac using some disk analyzer apps. They offer unique visual experiences and allow you to take practical steps to free up valuable disk space.
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How to check hard drive space on Mac
There are several ways to check the storage space on your Mac. Choose the Apple menu> About this Mac and click on Storage for the most basic. Hover your pointer over the colored blocks to see what type of content is using up disk space.
For more information, open the Disk Utility by searching for it with Spotlight ( Cmd + Space ). Select your startup volume from the left panel to check the amount of space used in the volume.
Then click on the button Info in the toolbar to display more details like the purgeable space and the available space (purgeable + free) .
For another method, right click on the hard drive icon Macintosh in the left sidebar of Finder and select Obtain informations . You will get details about the capacity used compared to the capacity available , as well as the space that macOS considers purgeable.
What is “Other” in Mac storage?
On some Macs, you will notice that the category Other storage takes a lot of disk space. This includes macOS system files, user library folders, cache folders, etc. The majority of these files are normally not visible.
If you play around with these directories, it could lead to unstable system, data loss or even prevent your Mac from starting up.
Why you should use a Mac disk space analyzer
Why would you use a third-party application when there are several built-in methods to check the disk space on your Mac? Here are a few reasons:
- The Finder may incorrectly interpret hard links as another copy of the file. Although hard links don’t take up actual disk space, the Finder counts them (at least) twice as separate files, resulting in an inaccurate estimate of folder sizes.
- Your Mac’s file system, APFS , uses space-saving clones when copying a file to the same volume. Instead of duplicating data, it updates metadata and data on disk is shared. Finder does not understand this mechanism and incorrectly estimates free and used disk space.
- The APFS snapshot feature works differently. When Time Machine creates local snapshots, the file system is aware of the changes. But neither the Finder nor About this Mac ne show the space occupied by the snapshots. Therefore, it can show that the category System takes a lot of space.
- In APFS, each disk is a container that can hold multiple volumes and shares the same pool of free space. If your startup disk consists of at least four separate volumes, you may notice a reduction in the available space on Macintosh HD .
Now that you know why we recommend using third-party apps, let’s explore the best Mac disk space analyzers to inspect and analyze disk space.
GrandPerspective is a utility application that uses a treemap structure to visualize disk space. On launch, it asks you to select a folder or drive that you want to scan. A viewport displays the content in colored rectangular blocks.
Hover your mouse pointer over a block to display the file name and size at the bottom of the display window. You can move the selection from one file to one of the folders and vice versa by changing the focus. Press on Cmd + [ et Cmd +] to move up and down in the file hierarchy.
Click on a block to lock the selection. Then you can act directly on this element. Press on Space to take a quick look and click the button Reveal to display the selected file / folder in Finder.
What makes GrandPerspective unique?
- You can change the sorting criteria by creation date, extension, file type or folder and even choose a different color scheme.
- Select from the list of recently scanned cases to save time. Or select Load scan data to create a new view with older scanned data.
- Create new filters to refine the view, and run filter tests to mix them up in different ways. You can choose from audio, hardlinks, images, app package content, etc.
- The app allows you to rescan a folder with different settings. Then open those results in a separate window to compare with the latest results.
Download: GrandPerspective (free)
OmniDiskSweeper is another disk space analyzer for Mac. At launch, select a drive from the list and click on Scan the selected drive . A new window opens with folders and files displayed in a column view. After the scanning process is complete, click on a folder and browse to any file that takes up large disk space.
The application uses different colors to group files by size and to display the status of an item. The file sizes marked in green are the smallest files. As the size increases, it turns dark green, dark purple, and light purple for large files. Double-click an item to open it in Finder.
What does OmniDiskSweeper offer?
- It allows you to scan external and disk drives located on your network. If you share a folder located on a PC, the app can even scan that folder.
- The bottom window provides you with detailed information about a file, its size, and the packages it belongs to in the file system. You need to focus on the files that are not part of the packages.
Download: OmniDiskSweeper (free)
3. Disk X inventory
Disk Inventory X is a utility application that gives you an overview of the space occupied by different types of files. Open menu File and select any drive or folder you want to scan. Once the scanning process is complete, the application creates a graphical treemap to visualize the storage space.
The left panel helps you sort the file list based on the colors associated with a particular file type, size, number of files, and file format. Click any item on the chart to help identify and locate the largest files.
Unique Features of Disk Inventory X:
- Any selection you make in the treemap graph is synchronized with the finder view. This helps you find the main culprits no matter where they are on the drive.
- The application sorts the file types in descending order. Each file type has a color used in the treemap graphic and in all open folders.
- You can view package contents, zoom in folders, and hide free space to analyze disk space in various ways.
Download: Disk Inventory X (free)
DaisyDisk is a beautifully designed disk analyzer that uses a sunburst board to show you an overview of the disk. At launch, it displays all mounted volumes with different color styles. Green means at least half of your drive is empty, while red means it’s time to act.
Click on the button Digitize , and in a few seconds you will see the map with a brief preview on the sidebar. Hover your mouse over any segment to see its content in the sidebar. When you want to go to the parent folder, click in the center of the disk map.
Key features of DaisyDisk
- The sunburst card helps you separate large files from smaller files. Explore and find out which items are consuming the most disk space.
- If you scan the disk as an administrator, it may reveal more data about hidden files on other volumes, space taken by local snapshots, and details of purgeable space.
- You can preview any file from the sidebar, send them to a collector panel, and then delete them at your convenience.
Download: DaisyDisk ($ 9.99, free trial available)
NCDU is a command line disk analyzer with an ncurses interface. It is based on the order of , but it’s much faster and easier to use on your Mac and remote servers. To get started, you’ll need to install the app through Homebrew.
Once installed, open Terminal and type ncdu / to start analyzing your drive. Use the arrow keys to browse the items. Then press i to view the details of the selected item.
Unique features of NCDU
- You can use various options to enhance the disc information. Access the NCDU man page for more details.
- It is easy to export all information to an output file. You can then use file comparison applications to better analyze your disk usage.
Download: NCDU (free)
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Stay on top of your Mac’s free space
Getting precise details about the free and used space on your Macis is tricky. Although there are many built-in techniques, most of them are unreliable for detailed use. Use the Disk Utility and these applications to inspect and analyze in detail your storage space.