You double-click an app you just downloaded and macOS stops you cold: “macOS cannot verify the developer of ‘AppName’. Are you sure you want to open it?” — sometimes worded as “app can’t be opened because it is from an unidentified developer.” Your Mac isn’t broken and the app usually isn’t malware. This is Gatekeeper doing its job. Here’s exactly what it means and the safe way to open the app.
What this message actually means
macOS checks every app you download for a valid Developer ID signature from Apple. When an app is signed but not notarized (the developer skipped Apple’s automated malware scan), or it’s from a small developer who never registered with Apple, Gatekeeper can’t confirm who made it — so it blocks the first launch. It is not saying the app is dangerous. It’s saying “I can’t vouch for who wrote this, so I’ll let you decide.”
This is a different dialog from “cannot verify this app is free of malware” and from “app is damaged and can’t be opened”, but the safe fixes below are the same.
Before you override: is the app actually trustworthy?
The override is only safe if you trust the source. Ask yourself:
- Did you download it from the developer’s real website or a known, reputable source — not a random link, ad, or “free download” mirror?
- Were you expecting to install this app, or did it appear after clicking something?
- Is it a well-known app (a popular open-source tool, a small utility from a named developer)?
If any answer is “no,” stop and delete the file. Overriding Gatekeeper on a file you don’t trust is exactly how Macs get infected. When the source is legitimate, continue.
Fix 1 — Right-click, then Open (try this first)
This is the safest method because it only creates an exception for this one app:
- Find the app in Finder (in your Applications folder or wherever you saved it).
- Right-click (or Control-click) the app icon and choose Open.
- The same warning appears, but now with an Open button. Click Open.
macOS remembers your choice, and the app launches normally from now on. If there’s no Open button — only Cancel/Move to Trash — use Fix 2.
Fix 2 — System Settings → “Open Anyway”
On macOS Ventura and later, the override moved into Settings:
- Try to open the app once (let it get blocked) so macOS logs the attempt.
- Open System Settings → Privacy & Security.
- Scroll to the Security section. You’ll see a line like “AppName was blocked to protect your Mac.”
- Click Open Anyway, then authenticate with Touch ID or your password.
On older macOS (Monterey and earlier) the same button lives in System Preferences → Security & Privacy → General.
Fix 3 — Clear the quarantine flag (Terminal, advanced)
If the first two fail — common with unsigned command-line tools or apps unzipped from certain archives — remove the quarantine attribute macOS added at download:
- Open Terminal (Applications → Utilities).
- Type
xattr -dr com.apple.quarantine(with a trailing space), then drag the app onto the Terminal window so its full path is filled in. - Press Return, then launch the app normally.
Only do this for an app you trust — it strips the safety flag entirely for that file. Don’t run sudo spctl --master-disable to turn Gatekeeper off system-wide; that lowers security for every future download, and modern macOS may not even honor it.
What you should NOT do
- Don’t disable Gatekeeper entirely. Override the single app, not your Mac’s protection.
- Don’t re-download from a “fixed” mirror that promises no warning — that’s a classic malware lure.
- Don’t enter your password into a pop-up you didn’t start. The real prompt only appears after you click Open Anyway in Settings.
Still blocked after all three?
If the app still won’t launch, the issue is usually the app itself, not Gatekeeper: a corrupted download (re-download from the source), an Intel-only app on Apple Silicon that needs Rosetta, or an app that’s simply too new for your macOS version. Check the developer’s stated minimum macOS requirement against yours (Apple menu → About This Mac).
The bigger picture: a Mac too old to update
If you keep hitting developer-verification and update walls because your Mac is stuck on an old macOS, it may be time to upgrade the machine itself. A newer Apple Silicon MacBook runs current apps and the latest security updates without constant overrides. If you’re weighing that, our certified refurbished MacBooks are a fraction of new-Mac prices — see the Apple clearance selection for the current deals, or trade in your old Mac toward one.
FAQ
Does “Open Anyway” disable my Mac’s security?
No. It creates a one-time exception for that single app. Gatekeeper still checks every other app you download.
Why can’t macOS verify the developer if the app is legit?
The developer either didn’t pay for an Apple Developer ID or didn’t notarize the app. Plenty of trustworthy small and open-source apps skip that step — it’s about paperwork, not danger.
Is the xattr quarantine command safe?
Yes, for an app you trust. It only removes the download-quarantine flag from that specific file so macOS stops blocking it. Never run it on files from an unknown source.
The app is from the App Store — why am I still blocked?
You’re not seeing this exact dialog from a true App Store install. If you do, the app was likely downloaded from the web with the same name — verify you launched the real App Store copy.