If your MacBook is running noticeably slower than usual, frequently showing the spinning beach ball, or displaying a warning that your startup disk is almost full, the first step in diagnosing and resolving the problem is checking exactly how much storage space is available and understanding what is consuming it. macOS provides a detailed, colour-coded storage breakdown that makes it easy to identify the largest categories of files and decide what to clean up.
Why Storage Matters on a Mac
macOS requires a certain amount of free disk space to function properly. The operating system uses your storage drive as virtual memory (swap space) when your RAM is full, and it needs room to write temporary files, install updates, and perform background tasks. When your drive is nearly full:
- The system may become slow or unresponsive
- Application launches slow down significantly
- Photos, video editing apps, and creative tools may refuse to work or crash
- macOS may fail to install software updates
As a general rule, aim to keep at least 10–15% of your drive capacity free at all times.
How to Check Storage on macOS Ventura, Sonoma, and Later
- Click the Apple menu () in the top-left corner of your screen.
- Select System Settings.
- In the left-hand sidebar, click on General.
- On the right side of the window, click on Storage.
- Allow a few moments for macOS to calculate the storage usage. A colour-coded horizontal bar will appear at the top of the screen, showing the total capacity of your drive and how much is used versus free.
- Hover your mouse over the different coloured segments in the bar to see the label and size of each category (Applications, System Data, Documents, iCloud Drive, iOS Files, etc.).
How to Check Storage on macOS Monterey and Earlier
- Click the Apple menu ().
- Select About This Mac.
- In the small window that appears, click the Storage tab at the top.
- The colour-coded bar will display your storage usage breakdown. Click the Manage… button to open the detailed Storage Management tool.
Built-In Storage Optimisation Tools
Once you are on the Storage screen, macOS offers several automated recommendations that can reclaim significant space with minimal effort:
- Store in iCloud: Automatically uploads your Desktop, Documents folder, and Photos library to iCloud, keeping only recently accessed files downloaded locally on your drive. Older files remain accessible on demand when you need them.
- Optimise Storage: Automatically removes local copies of Apple TV+ movies and TV episodes you have already watched, since they can be re-downloaded from Apple at any time.
- Empty Trash Automatically: Permanently deletes items that have been sitting in the Trash bin for more than 30 days, preventing you from accidentally hoarding deleted files indefinitely.
- Reduce Clutter: Click the “Review Files” button next to this option to see a list of your largest files sorted by size, making it easy to identify and manually delete old downloads, archived projects, or duplicate files you no longer need.