Apple Responds to Developers Regarding Expired Mac App Store Security Certificates

Last week some users and developers experienced an issue that displayed a "damaged" error when attempting to open select apps from the Mac App Store, including popular apps like 1Password, Tweetbot and Byword. Today, Apple has sent an email to developers explaining what happened and how to fix their apps.

CUDcjswUsAAiKe-
In the email, which developer Donald Southard Jr. shared on Twitter, Apple explains that the company issued a new security certificate for the Mac App Store in September in anticipation of the expiration of the old certificate. The new certificate used a stronger SHA-2 hashing algorithm instead of the old SHA-1 algorithm. Hashing algorithms are used by certificate authorities to sign security certificates.

However, two issues caused users to experience errors when starting up apps. The first issue, according to Apple, is that there was a caching issue with the Mac App Store that required users to restart their computers and re-authenticate with the Mac App Store to clear out the old cache. Apple says it's working on a fix for this in an upcoming OS X update. The other issue is that some apps were running an older version of OpenSSL that didn't support SHA-2. Apple says it replaced the SHA-2 certificate with a new SHA-1 certificate last Thursday night.

Finally, Apple says that "most of the issues are now resolved", but that some apps might still experience problems if the apps make "incorrect assumptions" about the Mac App Store's security certificates. Apple asks developers to make sure their code adheres to the Receipt Validation Programming Guide and to resubmit apps for expedited review if necessary. The AppleCare support team has also been briefed with the latest troubleshooting information for users.

Popular Stories

AirPods Pro Firmware Feature

Apple Releases New Firmware for AirPods Pro 2, AirPods Pro 3, and AirPods 4

Thursday November 13, 2025 11:35 am PST by
Apple today released new firmware designed for the AirPods Pro 3, the AirPods 4, and the prior-generation AirPods Pro 2. The AirPods Pro 3 firmware is 8B25, while the AirPods Pro 2 and AirPods 4 firmware is 8B21, all up from the prior 8A358 firmware released in October. There's no word on what's include in the updated firmware, but the AirPods Pro 2, AirPods 4 with ANC, and AirPods Pro 3...
iPhone Pocket Short

iPhone Pocket Now Available to Order, But Already Selling Out

Friday November 14, 2025 6:20 am PST by
Apple recently teamed up with Japanese fashion brand ISSEY MIYAKE to create the iPhone Pocket, a limited-edition knitted accessory designed to carry an iPhone. iPhone Pocket is available to order on Apple's online store starting today, in the United States, France, China, Italy, Japan, Singapore, South Korea, and the United Kingdom. However, it is already completely sold out in the United...
CarPlay Pinned Messages

iOS 26.2 Adds New CarPlay Setting

Thursday November 13, 2025 6:48 am PST by
iOS 26 extended pinned conversations in the Messages app to CarPlay, for quick access to your most frequent chats. However, some drivers may prefer the classic view with a list of individual conversations only, and Apple now lets users choose. Apple released the second beta of iOS 26.2 this week, and it introduces a new CarPlay setting for turning off pinned conversations in the Messages...
tvOS 26 Profiles

tvOS 26.2 Adds a Useful New Feature to Your Apple TV

Friday November 14, 2025 10:02 am PST by
Starting with the upcoming tvOS 26.2 update, currently in beta, additional profiles created on the Apple TV no longer require their own Apple Account. In the Settings app on the Apple TV, under Profiles and Accounts, anyone can create a new profile by simply entering a name and indicating whether the profile is for a kid. The profile will be associated with the primary user's Apple Account,...
Tim Cook WWDC 2018

Report: Tim Cook to Step Down as Apple CEO 'as Soon as Next Year'

Saturday November 15, 2025 2:40 pm PST by
Apple is preparing for Tim Cook to step down as CEO of the company "as soon as next year," according to the Financial Times. The company's board of directors and senior executives "recently intensified preparations for Cook to hand over the reins," the report said. While the report said that Apple is unlikely to name a new CEO before its next earnings report in late January, it went on to ...
apple silicon mac lineup 2024 feature purple m5

Apple's 2026 Mac Plans

Friday November 14, 2025 3:23 pm PST by
Most of Apple's Macs are slated to get M5 chips across 2026, and there's a possibility we'll even see the first M6 chips toward the end of the year. Updates are planned for everything from the MacBook Air to the Mac Studio. MacBook Air (Early 2026) The MacBook Air will be one of the first Macs to get a 2026 refresh, with an update planned for the first few months of the year. The MacBook...
walmart new ornametns

Walmart Black Friday Deals Begin Today With Low Prices on Headphones, TVs, and More

Friday November 14, 2025 7:55 am PST by
Walmart's Black Friday sale has officially kicked off today, with an online shopping event that's also seeing some matching deals in retail locations. There are quite a few major discounts in this sale, including savings on headphones, TVs, and more. Note: MacRumors is an affiliate partner with Walmart. When you click a link and make a purchase, we may receive a small payment, which helps us...
best early black friday deals

Best Black Friday Apple Deals Live Now - Save on AirPods, iPads, and Apple Watches

Saturday November 15, 2025 1:45 pm PST by
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When ...
iOS 26

iOS 26.2 Available Next Month With These 8 New Features

Tuesday November 11, 2025 9:48 am PST by
Apple released the first iOS 26.2 beta last week. The upcoming update includes a handful of new features and changes on the iPhone, including a new Liquid Glass slider for the Lock Screen's clock, offline lyrics in Apple Music, and more. In a recent press release, Apple confirmed that iOS 26.2 will be released to all users in December, but it did not provide a specific release date....
homepod mini thumb feature

New HomePod Mini, Apple TV, and AirTag Were Expected This Year — Where Are They?

Wednesday November 12, 2025 11:42 am PST by
While it was rumored that Apple planned to release new versions of the HomePod mini, Apple TV, and AirTag this year, it is no longer clear if that will still happen. Back in January, Bloomberg's Mark Gurman said Apple planned to release new HomePod mini and Apple TV models "toward the end of the year," while he at one point expected a new AirTag to launch "around the middle of 2025." Yet,...

Top Rated Comments

Bubba Satori Avatar
131 months ago
With all the ills in the world, you have time to be this bothered about this. Consider that for a moment.
This is not illsintheworldRumors.
Consider that for a moment.
Score: 15 Votes (Like | Disagree)
Ankou_Sabat Avatar
131 months ago
Actually this response does nothing about a much larger issue on the App Store.

Take the Tweetbot issue which I had hit me. They had released a new version, Tweetbot 2.1.1, right before this issue happened on Oct 15. This updated version is incompatible with Mac OS Mavericks (10.09) so those running Mavericks were stuck with the previous version. This means that for all those running an OS older than 10.10, you're only able to run Tweetbot 1.6.2. If you go to the App Store and try to update it, or even re-download on such an older OS it explicitly tells you of the incompatibility and says that it will download the "old" version for compatibility.

That would be fine, except the old versions are still signed with the EXPIRED CERTIFICATE! So even if you follow the directions to "re-download the damaged app" it will refuse to run because the certificate signed is expired. So the only "fix" is to upgrade your OS to 10.10. Sure it can be argued to upgrade to the latest version, but there are quite a few instances where this is impossible to do and as such, Apple has just put an expiration date on older software preventing you from running it by linking it to this certificate and not providing developers a way to re-sign those submissions with an updated cert. Neither does the App Store itself provide such a facility.

So if by the current expiration date which I believe now is 2 years from now, if your computer is unable to be upgraded to current OS and the current version is unsupported on your system, then you are completely out of luck and stuck with no app that you paid for. This makes the "download old version" feature in the App Store completely flawed if they provide no way to back sign older provided version on the store front.
Score: 11 Votes (Like | Disagree)
sw1tcher Avatar
131 months ago
Software is like that. It's always just about to fall down around our ears, except usually someone is there trying to stop that from happening. Sometimes there are screw ups.
Software purchased through the MAS is like that. From what I read, people who purchased the same software directly from the developer or through other means didn't have to deal with this nonsense.

In the good ol' days, prior to the existence of the MAS, online activation, and subscription services, I'd install a program and it would just work™ until it got replaced or the computer died.
Score: 9 Votes (Like | Disagree)
gijoeinla Avatar
131 months ago
Did someone at Apple win a prize for drafting a note with the most use of "issues" in the first paragraph? How did this letter get by Apple PR?

If Apple normally does one thing well, it's strong apologies once they've completed an investigation into a problem. This letter is not that.

Yes let's tear apart the letter for next 30 posts shall we. Let's question Apples integrity over it.

Oh my god. Get over it!
Score: 7 Votes (Like | Disagree)
applerocks Avatar
131 months ago
Did someone at Apple win a prize for drafting a note with the most use of "issues" in the first paragraph? How did this letter get by Apple PR?

If Apple normally does one thing well, it's strong apologies once they've completed an investigation into a problem. This letter is not that.
Score: 5 Votes (Like | Disagree)
alphaod Avatar
131 months ago
Maybe it'll get some developers to finally update their apps.
Score: 5 Votes (Like | Disagree)