“App is damaged and can’t be opened”
macOS
Low severity
macOS — “‘App’ Is Damaged and Can’t Be Opened. You Should Move It to the Trash”
Gatekeeper quarantined a downloaded app whose signature it can’t verify, or the download was incomplete.
Last reviewed 2026-08-29 by the Tech Issue Guide team.
Symptoms
- Opening a newly downloaded app shows “… is damaged and can’t be opened.”
- The app came from a website rather than the App Store.
- It happened right after moving the app or transferring it between Macs.
What causes “App is damaged and can’t be opened”
- macOS Gatekeeper quarantined the download because it cannot verify the developer signature or notarization.
- The download was truncated or the archive was corrupted.
- The app is genuinely unsigned (older or hobby software).
How to fix it — 3 steps
- Re-download the app from the developer’s official site over a stable connection and try again.
- If you trust the source, remove the quarantine attribute from the app bundle (command below).
- If needed, open System Settings → Privacy & Security, scroll to the blocked-app notice and click “Open Anyway.”
Terminal / CLI command
xattr -dr com.apple.quarantine "/Applications/YourApp.app"Replace the path with the actual app. Only do this for software you trust from a known source.
How to confirm the fix: The app launches normally and continues to open on subsequent tries.
Prevent it from coming back
Prefer the App Store or notarized downloads, and verify checksums when a developer provides them.
Frequently asked questions
Is removing the quarantine flag dangerous?
It bypasses one of Gatekeeper’s checks, so only do it for apps you obtained directly from a developer you trust. Never do it for software from unknown links.
Why does the Mac say ‘damaged’ when it isn’t?
It is misleading wording. In most cases the file is fine; macOS just cannot confirm its signature and defaults to the strongest warning.