Reclaim space on your Mac, using only the tools Apple built in

If your Mac has ever told you it is low on disk space, you already know the feeling: a yellow warning in the corner, a spinner instead of an app, and a vague suspicion that somewhere on this machine there are gigabytes that should not be there. This portal exists to fix that in the most boring, reliable way possible.

Mactria Help is a free educational reference maintained by Mactria Media LLC, an independent publisher based in San Francisco. We are not a software company, we do not sell an app, and we are not affiliated with Apple Inc. Every technique we describe is executed through software that ships with macOS. Where a task can be done two ways, we prefer the way that keeps a copy of your data somewhere safe.

Why built-in tools are enough

A modern macOS install already contains a full storage-management toolkit. Finder can sort every folder by size, System Settings > General > Storage presents a colour-coded map plus one-tap recommendations, iCloud can offload files on demand, Photos can detect duplicates and large videos, Mail can strip stored attachments, and Time Machine manages local snapshots automatically. Third-party “cleaner” utilities mostly wrap these same ideas in a dark-themed window and a yearly subscription.

We are not going to pretend that every Mac is one click away from empty. Large photo libraries, years of Mail attachments and developers’ build folders are genuinely big. The point of the guide is that each of those categories has a specific, inspectable place on your disk, and once you know where it lives, deleting safely becomes routine rather than scary.

What actually fills a Mac

Before you start deleting, it helps to see the shape of the problem. Apple’s Storage screen groups your disk into Applications, Documents, Photos, Mail, System Data and free space. The proportions below are a typical 512 GB MacBook; your own numbers are one click away in System Settings.

Illustrative proportions for a 512 GB MacBook. Your numbers will differ; the goal of the guide is to show you how to read your own bar.

Start with chapter one

The best route through this material is in order, because later chapters assume you can already read the Storage screen and find a folder’s real size. If you only have ten minutes, start with the Start Here chapter and the quick wins below.

• Empty the Bin and clear Recently Deleted in Photos.
• Remove leftover installer packages and disk images you have already used.
• Turn on Optimize Mac Storage in iCloud settings.
• Delete iOS device backups you no longer need in Finder.
• Check Storage in System Settings for one-tap recommendations.

Chapter index

1. 01Start hereHow to use the guide, storage basics, and how to open System Settings > Storage.
2. 02Storage overviewWhat actually fills a Mac: apps, photos, system data, mail and backups.
3. 03Finder workflowsSort by size, chase stray installers and tidy the folder they pile up in.
4. 04System DataThe “Other” category: caches, logs, iOS backups and local snapshots.
5. 05iCloud offloadOptimize Mac Storage, iCloud Photos, Desktop & Documents, offload versus delete.
6. 06Photos & videosDuplicates, screenshots, large videos and the Recently Deleted album.
7. 07Local snapshotsHow Time Machine backups quietly occupy your internal drive.
8. 08Mail & large filesMail attachments, Messages media and uninstalling apps properly.
9. 09Avoid third-party cleanersWhy built-in tools are enough and what to watch for in cleaner apps.

What this site is not

We do not provide a program to install, we do not offer remote assistance, and we never ask you to run a script that was pasted from a pop-up window. We do not guarantee any particular number of gigabytes recovered, because the amount depends entirely on what is on your machine. We publish a paid e-book for readers who want the whole method in one printable file, and we describe it honestly, with a price and a refund policy, on the e-book page.