Some Mac App Store Apps 'Damaged' Due to Expired Security Certificate - MacRumors
Skip to Content

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

by

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.

Tag: Mac App Store

Popular Stories

Mac App Store General Feature

Apple Removes Fake Crypto Wallet App That Stole $9.5 Million From Mac Users

Tuesday April 14, 2026 11:42 am PDT by
A fake Mac app designed to look like the real thing snuck past Apple's app review team, costing users $9.5 million in cryptocurrency. According to CoinDesk, a fake macOS version of the Ledger Live crypto wallet app scammed people into handing over access to their cryptocurrency wallets. More than 50 people fell victim to the fake app between April 7 and April 13. Ledger has an official...
Read Full Article • 175 comments
Dynamic Island iPhone 18 Pro Feature

11 Reasons to Wait for the iPhone 18 Pro

Monday May 11, 2026 9:01 am PDT by
We're only four months out from the launch of Apple's premium next-generation smartphone lineup, and while we're not expecting a sea change in terms of functionality, there are still several enhancements rumored to be coming to the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth noting is that Apple is reportedly planning a major change to its iPhone release cycle this year, adopting a...
Read Full Article • 35 comments
iOS 26

iOS 26.5 Features: Everything New in iOS 26.5

Monday May 11, 2026 5:09 pm PDT by
Apple released iOS 26.5 after a few months of beta testing, and while it doesn't have the Siri features we were hoping for since those are being held until iOS 27, there are a handful of useful changes worth knowing about. Subscribe to the MacRumors YouTube channel for more videos. End-to-End Encryption for RCS Support for end-to-end encryption (E2EE) for RCS messages between iPhone and...
Read Full Article • 65 comments

Top Rated Comments

R
Razeus
137 months ago
Welcome to Tim Cook's Apple...

It Just Works is a thing of the past.
Score: 11 Votes (Like | Disagree)
pianojoe Avatar
pianojoe
137 months ago
Now, this is embarrassing.
Score: 8 Votes (Like | Disagree)
T
Tiger8
137 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)
lysingur Avatar
lysingur
137 months ago
I'm actually kind of glad that Apple isn't planning on making any cars. Oh, wait...
Score: 7 Votes (Like | Disagree)
canesalato Avatar
canesalato
137 months ago
And Scott Forstall was kicked out because he didn't apologize for Maps?
Score: 6 Votes (Like | Disagree)
K
konqerror
137 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)
Read All Comments