As a developer I know that if an app is not signed and downloaded from the internet, macOS shows a message to the user when he first tries to open and that they may need to right click->open or clean the xattr from it.

I have noticed though that there are different messages, like:

"App" can't be opened because Apple cannot check it for malicious software.

"App" cannot be opened because the developer cannot be verified.

And the more scary looking :

"App" is damaged and can't be opened. You should move it to the Trash.

I have seen all of the above messages in different open source projects, so none of them should be a "this is illegal software" warning and all of them worked as they should, after making the os skip this message.

Why are there all these different messages?

Edit: I'm not saying that ALL apps that show an "is damaged" get fixed by removing the quarantine flag, I say that some of them do!

  • @Giacomo1968 while you should be right, you sadly are not. As benwiggy explains bellow it is quite possible
    – Ant
    Oct 8, 2023 at 16:01

1 Answer 1


There doesn't seem to any documentation on exactly when these messages are triggered.

In my experience, the "damaged" message does not relate to the quarantine flag, nor unsigned apps, but occurs for signed software that has been altered.

This could amount to very trivial changes, like datestamps. I've even seen this on perfectly 'legal' apps migrated from another Mac.

Apple may deliberately be using 'scary language' that isn't entirely accurate: I suspect that "can't check it for malware" just means that hardened run-time settings (or other security configurations, like sandboxing) aren't used, which means the OS can't 'tick some boxes' about what the app might do.

  • It is quite obvious that apple is leaning towards overly cautious in their messages. I do find it interesting though that even the damaged message disappears on removing the quarantine flag
    – Ant
    Oct 8, 2023 at 16:03
  • @Ant I've tried removing the quarantine flag, but still the app reports as damaged, so there may be even more to it!
    – benwiggy
    Oct 8, 2023 at 16:17
  • Hyper specific example: github.com/RimSort/RimSort/releases -> RimSort-Edge_d9cf3f6_Darwin_i386.zip on arm Mac shows the damaged alert. After xattr -cr it opens fine
    – Ant
    Oct 8, 2023 at 16:51

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