Some Mac App Store Apps 'Damaged' Due to Expired Security Certificate

A growing number of MacRumors readers and Twitter users have been experiencing an issue with some Mac App Store apps displaying a "damaged" error when opened since late Wednesday. The issue has affected popular apps such as 1Password, Acorn, Byword, DaisyDisk and Tweetbot.

Damaged-Mac-App-Store-Apps

Mac App Store apps with a "damaged" error (Image: Graham/Twitter)

Mac users are prompted with this error message when opening Mac App Store apps:

“App Name” is damaged and can’t be opened. Delete “App Name” and download it again from the App Store.

Tweetbot developer Paul Haddad tweeted that the issue appears to be related to security certificates that expired on November 11, 2015, and he further speculated that the receipts now using SHA256 encryption may be causing problems with older OS X versions.

The issue, however, also appears to affect some users running OS X El Capitan, leading Haddad to believe that Mac App Store apps contacting Apple's servers simultaneously may be causing a "self inflicted DDOS on Apple’s receipt generation service."

Haddad says that rebooting your Mac on OS X 10.10 or later may resolve the issue, while some users have been forced to reinstall apps from the Mac App Store, disconnect from and reopen the Mac App Store or simply reenter their Apple ID password.

It appears that Apple has since set a new 2035 expiration date for the security certificates, per The Guardian, at least some for apps, but the issues are persisting for some. Apple did not respond to request for comment.

Update: Rene Ritchie at iMore has further explained what's causing Mac apps to report as "damaged" and what can be done about it.

Popular Stories

iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Coming Soon With These 14 New Features

Friday July 4, 2025 1:05 pm PDT by
Apple's next-generation iPhone 17 Pro and iPhone 17 Pro Max are just over two months away, and there are plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models. Latest Rumors These rumors surfaced in June and July:Apple logo repositioned: Apple's logo may have a lower position on the back of the iPhone 17 Pro models, compared to previous...
Apple Watch Ultra Night Mode Screen

Apple Watch Ultra 3 Launching Later This Year With Two Key Upgrades

Wednesday July 2, 2025 1:13 pm PDT by
The long wait for an Apple Watch Ultra 3 appears to be nearly over, and it is rumored to feature both satellite connectivity and 5G support. Apple Watch Ultra's existing Night Mode In his latest Power On newsletter, Bloomberg's Mark Gurman said that the Apple Watch Ultra 3 is on track to launch this year with "significant" new features, including satellite connectivity, which would let you...
iPhone 17 Pro in Hand Feature Lowgo

iPhone 17 Pro Max Battery Capacity Leaked

Thursday July 3, 2025 5:40 am PDT by
The iPhone 17 Pro Max will feature the biggest ever battery in an iPhone, according to the Weibo leaker known as "Instant Digital." In a new post, the leaker listed the battery capacities of the iPhone 11 Pro Max through to the iPhone 16 Pro Max, and added that the iPhone 17 Pro Max will feature a battery capacity of 5,000mAh: iPhone 11 Pro Max: 3,969mAh iPhone 12 Pro Max: 3,687mAh...
airpods pro 2

AirPods Pro 3 to Help Maintain Apple's Place in Earbud Market Amid Increasing Low-Cost Competition

Thursday July 3, 2025 7:25 am PDT by
Apple's position as the dominant force in the global true wireless stereo (TWS) earbud market is expected to continue through 2025, according to Counterpoint Research. The forecast outlines a 3% year-over-year increase in global TWS unit shipments for 2025, signaling a transition from rapid growth to a more mature phase for the category. While Apple is set to remain the leading brand by...
iphone 16 pro models 1

Here's How the iPhone 17 Pro Max Will Compare to the iPhone 17 Pro

Saturday July 5, 2025 1:00 pm PDT by
Apple should unveil the iPhone 17 series in September, and there might be one bigger difference between the Pro and Pro Max models this year. As always, the Pro Max model will be larger than the Pro model:iPhone 17 Pro: 6.3-inch display iPhone 17 Pro Max: 6.9-inch displayGiven the Pro Max is physically larger than the Pro, it has more internal space, allowing for a larger battery and...
apple silicon mac lineup 2024 feature purple m5

Apple's Upcoming Macs Listed in New Report

Thursday July 3, 2025 9:09 am PDT by
AppleInsider's Marko Zivkovic today shared a list of alleged identifiers for future Mac models, which should roll out over the next year or so. The report does not reveal anything too surprising, but it does serve as further evidence that Apple is seemingly working on new models of every Mac, including the MacBook Air, MacBook Pro, iMac, Mac mini, Mac Studio, and Mac Pro. Apple is...

Top Rated Comments

Razeus Avatar
126 months ago
Welcome to Tim Cook's Apple...

It Just Works is a thing of the past.
Score: 11 Votes (Like | Disagree)
pianojoe Avatar
126 months ago
Now, this is embarrassing.
Score: 8 Votes (Like | Disagree)
lysingur Avatar
126 months ago
I'm actually kind of glad that Apple isn't planning on making any cars. Oh, wait...
Score: 7 Votes (Like | Disagree)
Tiger8 Avatar
126 months ago
I said it before and I say it again, Apple is falling behind in the software department. The number of bugs seems to increase with every release for either OSX or iOS. They still haven't resolved the iCloud backup issue, they should be embarrassed.
Score: 7 Votes (Like | Disagree)
canesalato Avatar
126 months ago
And Scott Forstall was kicked out because he didn't apologize for Maps?
Score: 6 Votes (Like | Disagree)
konqerror Avatar
126 months ago
This is yet another Apple services fail. What happens if you're outside of Internet access, say you're going to give a presentation?

The cert is valid for 5 years, so they should make the system automatically refresh when the cert has a year or even 6 months left to go.

Even Microsoft's DRM is better than Apple's. For time-limited (corporate) activation, it starts trying to contact the activation server after a month, but will let you go 6 months without locking you out.
Score: 6 Votes (Like | Disagree)