How can we help?

A Mac with macOS 14 Sonoma or later, with Apple silicon or an Intel processor.

Disk Advisor also needs macOS 26 or later on a Mac that supports Apple Intelligence, with Apple Intelligence turned on in System Settings. Everything else works on any supported Mac.

1. Download Diskfern from the Download page.
2. Open the downloaded file and move Diskfern to your Applications folder.
3. Open Diskfern from Applications. The first time, macOS asks you to confirm that you want to open it.

In the sidebar, choose This Mac to scan your whole startup disk, Home for your home folder, or Choose Folder… for any folder or connected drive. The File menu has the same choices: Scan Folder…, Scan Home and Scan Now.

Diskfern scans on your Mac and never uploads your files or the results. While Diskfern is open, it keeps the map up to date as files change.

No, Diskfern works without it. Without Full Disk Access, macOS keeps some folders private, such as Mail, Messages and Safari data, so Diskfern can’t measure them. When that happens, a banner tells you how many folders couldn’t be read.

To give access:

1. Choose Allow Full Disk Access in the banner, or open System Settings › Privacy & Security › Full Disk Access.
2. Turn on Diskfern.
3. Quit and reopen Diskfern, then scan again.

Diskfern › Settings › Permissions shows which permissions Diskfern has.

No. Files and folders stored only in iCloud are left in the cloud, so a scan never fills your disk with downloads. Diskfern counts the space files actually use on your Mac.

Hidden Space is the difference between the space macOS reports as used and what the folders Diskfern could scan add up to. It usually includes system files, local snapshots, purgeable space and folders macOS didn’t let Diskfern read. It overlaps with what System Settings calls System Data.

Select Hidden Space in the map to see what it may include. Giving Full Disk Access usually makes it smaller.

Treemap shows the files and folders in your scan as rectangles sized by the space they use. List sorts items by size. Sunburst shows folders as rings around the folder you’re in. Switch between them at any time; choose the view Diskfern opens with in Settings › General.

Use Diskfern Finder to search in plain language, for example “videos larger than 1 GB” or “PDFs from this month”, and narrow the search to This Mac, Home, Documents, Downloads or Desktop. Your recent searches are kept on your Mac only.

Smart Highlights group common storage, such as developer caches, logs, downloads and app data, into categories, each with a safety label. The labels help you tell rebuildable clutter apart from files worth reviewing before you remove anything.

Select it and press Space to preview it with Quick Look, or open the Inspector to see its size, location, dates and kind.

Add items to the Collector as you explore, then review them together. When you clean up, Diskfern asks you to confirm with Touch ID or your password and checks each item again just before removing it. Gathering items is free; cleaning up from the Collector is part of Pro and Family.

Diskfern never removes protected system locations or your main folders, such as your home, Documents or Applications folder. These rules are always on and are listed in Settings › Safety & Rules.

Only if you choose to. Cleanups start with Move to Trash by default, so you can put items back from the Trash in Finder. Permanently deleting is a separate choice in the confirmation, and you can keep Move to Trash as the default in Settings › Safety & Rules. Items you delete permanently can’t be recovered by Diskfern, so keep a backup, for example with Time Machine.

Open the Trash in the Dock, select the item and choose File › Put Back.

Yes, with Pro or Family. Open Applications in the sidebar, select an app and choose to uninstall it. Diskfern can’t remove apps that come with macOS, apps that are running, or itself. Apps installed for all users are moved to the Trash through Finder, which asks for an administrator password.

Disk Advisor answers questions about your storage, such as what a folder is for or whether a cache is safe to remove. It uses Apple’s on-device language model, so your questions and answers stay on your Mac. It is part of Pro and Family.

Answers are generated automatically and can be wrong, so check them before you act. Disk Advisor can add items to the Collector for you to review, but it never removes anything itself.

Disk Advisor needs macOS 26 or later on a Mac that supports Apple Intelligence, with Apple Intelligence turned on and its model downloaded. Diskfern tells you which of these is missing.

1. After you buy, we email your license key. It looks like DFRN-XXXX-XXXX-XXXX-XXXX.
2. In Diskfern, open Settings › License and enter the key.
3. The paid features turn on right away. Once activated, they also work offline.

Pro covers one Mac. Family covers up to 5 Macs in one household. If all of them are in use, Diskfern shows the Macs that are active so you can choose one to deactivate.

On the old Mac, open Settings › License and choose Deactivate This Mac, then activate on the new one. If you no longer have the old Mac, sign in to your account and deactivate it there.

Sign in to your Diskfern account with the email address you used at checkout; we email you a sign-in code. Your account shows your license keys, the Macs each one is active on and your orders. You can also open it from Diskfern › Settings › License.

Diskfern checks for updates about once a day and tells you when one is available. It never installs an update without your approval. To check now, open the Diskfern menu and choose Check for Updates…

Sign in to your account, open Orders and choose Request a refund next to the order, within 30 days of your purchase. You can also get there from Diskfern › Settings › License › Request a Refund. See the Refund Policy for details.

Your files and storage analysis stay on your Mac. If Diskfern crashes, it can send a limited technical crash report to help us fix the problem. Reports never include file names, file paths, file contents, search queries or license keys, and you can turn them off in Diskfern › Settings › Privacy. Read the Privacy Policy for everything we collect.

Open Settings › License and enter the key from your purchase email (check your spam folder if you can’t find it). Your key is also in your account. Activation needs an internet connection the first time.

macOS protects some folders. Give Diskfern Full Disk Access, then quit, reopen and scan again. See Full Disk Access above.

Email support@diskfern.com. In Diskfern, Help › Contact Support starts an email with your Diskfern version, macOS version and Mac model already filled in, which helps us answer faster.