Why Storage Studio asks for Full Disk Access

Full Disk Access is a macOS permission that lets an app read folders macOS normally protects, such as Documents, Desktop and Downloads. Storage Studio asks for it so it can see where your space is going and move or clear files without being blocked part-way. You grant it once in System Settings; you can skip it and grant it later.

Why it's needed

The request explains three things:

• See where your space is going. Without it, Storage Studio can't tell which folders are large or which files haven't been touched in months.
• Move files without breaking them. Moves, clear-ups and scans need to read every file they touch. What a move keeps is explained in What a move keeps.
• Your files stay on your Mac. Storage Studio looks at sizes and dates to suggest what's safe to move. Granting the permission doesn't send anything anywhere — see Privacy: what stays on your Mac.

How to grant it

When the request appears, System Settings opens at Privacy & Security → Full Disk Access for you.

1. Find Storage Studio in the list and switch it on.
2. Come back to Storage Studio. It notices within a couple of seconds and carries on — no restart needed.

If you skipped it, or Storage Studio isn't in the list:

1. Open Settings… in Storage Studio and choose Advanced.
2. In Permissions, click Show Storage Studio in Finder, then Open Full Disk Access.
3. Click + and choose Storage Studio, or drag the app from the Finder window into the list.
4. Switch it on, then click Re-check.

The Permissions page in Settings also shows whether it's granted, with an Open Settings button.

How Storage Studio knows

macOS doesn't tell apps when a permission changes, so Storage Studio checks for itself by trying to read a few protected files.

%% caption: How Storage Studio decides whether it has Full Disk Access
flowchart TD
  A[Try to read a few protected files] --> B{Did macOS refuse any of them?}
  B -->|Yes| C[Not granted]
  B -->|No| D{Could it read at least one?}
  D -->|Yes| E[Granted]
  D -->|No| F[Can't tell, so treated as not granted]

Any refusal counts as "not granted", and "can't tell" is never treated as a yes. It checks at launch, when you open the app, while the request window is open, and again whenever macOS actually refuses it a file.

Without it

Storage Studio still runs, but it can't read everything:

• macOS may ask you the first time it touches each protected folder.
• Anything it can't read is left out of scans, moves and clear-ups.
• The menu bar icon shows a yellow dot, the App permissions row in Services turns red, and the notification bell shows Full Disk Access needed with a Grant access button.

When it stops working

macOS ties the permission to the exact copy of the app, so an update or repair can quietly drop it. Storage Studio tells you Your Mac has stopped honouring this permission. Switch Storage Studio off and back on in the Full Disk Access list to restore it. If it's on but still not detected, see Full Disk Access is on but the app says it isn't.

Some folders belong to other apps and stay off-limits even with Full Disk Access. Storage Studio reports those as refused without sending you to change a setting that wouldn't help.

See also: The permissions Storage Studio asks for, Your first launch.