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As of macOS 10.12 Sierra, Apple computers have a so-called gatekeeper. This is supposed to protect the Mac, but can also lead to the error "XYZ.app is damaged and cannot be opened ..." to lead. What you can do to ensure that the app you have chosen opens, I will explain in this guide. It is important that the Gatekeeper is only one of the possible causes for the error message shown.
The error message: XYZ.app is damaged and cannot be opened
The full error message on your Apple Mac, iMac, or MacBook is likely to be as follows: "XYZ.app" is damaged and cannot be opened. We recommend moving the item to the trash. - In the corresponding window you then have the choice between Abort and Put it in the paper basket. If the .app file you downloaded from the Internet or some other third party source is damaged, it may be worth deleting and re-downloading it. If you are sure that it is not damaged or incomplete, or if you have performed the download again, then it may help to deactivate the Mac Gatekeeper.
Run an undamaged app thanks to the deactivated gatekeeper
As mentioned in the Mac Gatekeeper article linked at the beginning, you can use the security mechanism of macOS with a simple PortDisable and re-enable command. In order to solve the problem described above, close the app in question or the error message (with "Cancel") and open it Port. There you proceed as follows:
- Enter this command to deactivate Gatekeeper and confirm with Enter:
sudo spctl --master-disable
- If you are asked, enter the admin password and also confirm
- Open the app that was reported as damaged
- Activate the gatekeeper again with this command and its confirmation:
sudo spctl --master-enable
- Close the terminal and use the program in question
Don't forget to turn the Mac's security back on (step 4). Because it protects the Mac from malware and thus from damage to macOS and your files. If possible, only download apps from the official Mac App Store or directly from the developer. From purchase via download portals I advise you against.
Update 24.12.2020/XNUMX/XNUMX: Create exception for program
If the tips above don't help, it could be that macOS still doesn't want to open the program. In this case you have to create an exception in the security settings. I have how this works explained here in the article.
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.
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