Is Storage Studio safe to install?

Yes. Each Storage Studio release is signed with its developer's Apple Developer ID and notarised by Apple, which means Apple has checked it for malicious software before you ever download it. Download it only from storagestudio.us, and macOS checks the signature again every time it opens.

Where to download it

Get Storage Studio from the download page on storagestudio.us. It always gives you the current release. Copies from other websites, file-sharing services or someone else's disk may be old or altered, so it's best to avoid them.

Storage Studio 4.18 and later need a Mac with Apple silicon; Intel Macs stay on version 4.17.1. See Apple silicon and Intel Macs.

What signed and notarised mean

• Signed — the app carries a digital signature from its developer, Techtonic Systems Media and Research LLC, issued through Apple. If anyone changes the app after it was signed, the signature no longer matches and macOS notices.
• Notarised — before release, the app is sent to Apple, which scans it for malicious software and records that it passed. macOS checks for that record when you open the app.

How to check it yourself

1. The first time you open Storage Studio after downloading it, macOS shows a message that it was downloaded from the internet and that Apple checked it for malicious software and found none. Click Open.
2. To look later, choose Apple menu → About This Mac → More Info → System Report, then Software → Applications, and select Storage Studio. Obtained from should say Identified Developer.

If macOS instead says the app is damaged or can't be checked, don't work around the warning. Delete that copy and download a fresh one from storagestudio.us. See macOS says the app can't be opened.

%% caption: How a copy of Storage Studio reaches your Mac safely
flowchart LR
  A[Release is signed by the developer] --> B[Apple notarises it]
  B --> C[You download it from storagestudio.us]
  C --> D{macOS checks it when you open it}
  D -->|Signature matches| E[Storage Studio opens]
  D -->|Changed or unsigned| F[macOS blocks it]

Updates are checked too

When Storage Studio updates itself, it checks that the downloaded update matches the one our servers published, and that Apple has notarised it, before it replaces the app. If either check fails, it stops and the app you have stays as it is. See Keeping Storage Studio up to date.

Safe to install is not the whole story

Installing is only the start. Storage Studio is also built to be careful once it's running:

• it asks only for the permissions it needs — see The permissions Storage Studio asks for;
• a move copies first and removes the original only after the copy has finished, and most changes can be undone — see How Storage Studio keeps every change reversible;
• deleting goes to a recoverable place wherever possible — see How Storage Studio deletes things;
• your files stay on your Mac or go only where you send them — see Privacy: what stays on your Mac.

See also: Installing Storage Studio · Uninstalling Storage Studio · What leaves your Mac