Apps downloaded from Mac App Store won't open

Question

Apps downloaded from Mac App Store won't open

I am experiencing an issue after installing a 500 GB SSD inside of my iMac 21,5" Mid 2011.

The installation of the OS went smooth and everything seems to be working fine, except when I tried to open some apps that I've downloaded from the Mac App Store. They all share the same error code "Code Signature Invalid" and that's driving me insane trying to figure out what's the cause of it.

So far I have tried to check and repair the SSD through Disk Utility, booting the machine using Safe Mode but none of these solutions seem to have worked for me.

I could try to reinstall the OS if that could fix my issue, but I want to know if there is any other workaround that might be simpler.

I am currently running Mac OSX High Sierra 10.13.6.

Thank you for your help!

iMac 21.5″, macOS 10.13

Posted on Nov 18, 2020 9:14 AM

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Answer 1

Nov 19, 2020 6:55 PM in response to Lukas_ItalianWriter

I have the same issue as well as many other people. The issue has been reported in eight different discussion threads that I know of.

https://discussions.apple.com/thread/252030900

https://discussions.apple.com/thread/252037712

https://discussions.apple.com/thread/252032870

https://discussions.apple.com/thread/252060316

https://discussions.apple.com/thread/252056821

https://discussions.apple.com/thread/252061206

https://discussions.apple.com/thread/252030032

https://discussions.apple.com/thread/252059424

Observed behaviour is:

Almost all apps downloaded from the Apple App Store crash with a 'Code Sign Invalid' error (CODESIGNING).

It's not conclusive, but the issue seems to...

...have started around Wednesday last week (2020.11.11);

...affect macOS High Sierra (all versions, unpatched and patches);

...affect systems which have had the operating system recently reinstalled;

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Answer 2

Nov 23, 2020 4:28 PM in response to Lukas_ItalianWriter

I'm posting a request from PeterPeterPeterPeter (https://discussions.apple.com/thread/252030900?answerId=253955318022&page=2) for us to report this issue on the two Apple Feedback resources below...

Please help by reporting to Apple here https://apple.com/feedback

and here https://feedbackassistant.apple.com !

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Answer 3

Dec 5, 2020 1:30 AM in response to Lukas_ItalianWriter

Hey guys!! I think that I've found a working solution to this issue. It relies on some sort of verification that is sent towards Keychain, that might've been bugged during one of the latest security updated pushed for High Sierra.

This is the thread of the solution, as @PeterPeterPeterPeter wrote:

https://discussions.apple.com/thread/252030900

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Answer 4

Nov 19, 2020 7:01 AM in response to Lukas_ItalianWriter

Hey all,

I have the exact same issue on my MacBook Pro Late-2011 which I just restored today to its latest macOS version. (High Sierra 10.13.6)

Allegedly, the support for High Sierra will run out shortly (end of November) so I highly hope that Apple will fix this issue with a last Security update so that we can continue to use the legacy devices.

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Answer 5

BDAqua

Level 10

250,253 points

Nov 18, 2020 2:31 PM in response to Lukas_ItalianWriter

Thanks for the report.

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Answer 6

Nov 19, 2020 1:04 PM in response to Lukas_ItalianWriter

Anyone else with this issue? I badly need some essential apps such as GarageBand or iMovie, they worked like a charm previously but it's so frustrating that I can't open them.

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Answer 7

Nov 18, 2020 1:36 PM in response to Lukas_ItalianWriter

I have some news about this issue. I've tried reinstalling the OS and formatting once again my SSD in order to fix any potential troubles with it. It worked fine and I managed to download GarageBand, iMovie and all the iWork apps on my Mac and they all worked flawlessly. The issue began once again as I installed the security update code 2020-006 for High Sierra. I hope that Apple will regard this issue and release a solution as soon as possible!

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