MacOS 15 Certificate Validation Issues for Flutter Build

[MatthewJones517]

Description

After the forced update to macos-15 on 8/25/25, we're having issues with iOS certificate validation. These issues do not occur when using macos-14.

Here's the pipeline output:

No valid code signing certificates were found
You can connect to your Apple Developer account by signing in with your Apple ID
in Xcode and create an iOS Development Certificate as well as a Provisioning 
Profile for your project by:
  1- Open the Flutter project's Xcode target with
       open ios/Runner.xcworkspace
  2- Select the 'Runner' project in the navigator then the 'Runner' target
     in the project settings
  3- Make sure a 'Development Team' is selected under Signing & Capabilities > Team. 
     You may need to:
         - Log in with your Apple ID in Xcode first
         - Ensure you have a valid unique Bundle ID
         - Register your device with your Apple Developer Account
         - Let Xcode automatically provision a profile for your app
  4- Build or run your project again
  5- Trust your newly created Development Certificate on your iOS device
     via Settings > General > Device Management > [your new certificate] > Trust

For more information, please visit:
  https://developer.apple.com/library/content/documentation/IDEs/Conceptual/
  AppDistributionGuide/MaintainingCertificates/MaintainingCertificates.html

Or run on an iOS simulator without code signing
════════════════════════════════════════════════════════════════════════════════
No development certificates available to code sign app for device deployment

The iOS certificate install task is completing without errors:

 - task: InstallAppleCertificate@2
        displayName: 'Install Apple Distribution Certificate'
        inputs:
          certSecureFile: '2025-apple-dist-cert.p12'
          certPwd: '$(APPLE_DIST_CERT_PASSWORD)'
          keychain: 'temp'

Also, just to reiterate, when I force the VM back to macos-14 the issue isn't present.

I couldn't find any documentation about required codesigning changes for macos-15. Can someone please look into this? I believe something is broken on the image.

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 22.04
• Ubuntu 24.04
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

https://github.com/actions/runner-images/blob/main/images/macos/macos-15-arm64-Readme.md#xcode

Is it regression?

https://github.com/actions/runner-images/blob/main/images/macos/macos-14-arm64-Readme.md#xcode

Expected behavior

Flutter build completed without errors.

Actual behavior

Flutter build fails with certificate error.

Repro steps

0.) Use the macos-15 image
1.) Clone down a Flutter app
2.) Install the iOS codesigning certificate using the Microsoft step
3.) Run the Flutter Build task

[MatthewJones517]

Also I should point out that forcing the Xcode version to Xcode 16.4 did not resolve the issue.

[Mad4T]

We are having the exact same issue

[ijunaidm1]

Hi @MatthewJones517 - We are working on investigating this issue and will update you shortly
.

[archita105]

Hi @MatthewJones517 ,
Can you please provide the complete logs from a recent failed build as well as the codebase from which the problem is occurring and please include a link to the particular workflow runs that are failing if your project is open source.

[MatthewJones517]

@archita105
That's not something I can do. This is an Azure Devops pipeline. I recognize that this is the Github Actions repo, but the Devops Docs link out to this repo when referencing installed software on the agent images.

Sharing our codebase and logs would constitute a security violation with my employer.

[erik-bershel]

Hey @MatthewJones517! 👋

I have to add a few points to the discussion.

The problem appears when switching from macOS 14 to macOS 15. This is not an image regression in the usual sense of the word - each new OS has some differences in security systems and the kernel, which significantly affect the behavior. We cannot guarantee absolute compatibility of projects between the two OS. For us such changes are external.

I cannot say that your case is related to this kind of changes that are not related to the image configuration that we can influence, because we do not have enough information to process. We really need examples or full reproduction steps to continue the investigation.

Let's hope that information will be provided by users here or in this public forum thread. Otherwise, we cannot promise any quick results in the foreseeable future. 🤷

At this point we can only guess at the failure area, which may be related to one or more of the following factors: our image configuration, updates on the Apple side for macOS 15, changes on the Flutter side, InstallAppleCertificate@2 compatibility with macOS 15, or something else that cannot be guessed from the description.

[MatthewJones517]

@erik-bershel

Following the reproduction steps I provided above I've created a default Flutter app (using flutter create _____) and a pipeline that demonstrates the issue.

I've attached the raw log file from DevOps. You can find the code base here:
https://github.com/MatthewJones517/macos_15_image_issue_reproduction

raw-log-file.txt

[archita105]

Hi @MatthewJones517,

I reviewed the codebase and noticed that the DEVELOPMENT_TEAM value is currently set to an empty string DEVELOPMENT_TEAM = "";
, which may be causing the signing error.

Please update it to use the correct Team ID, for example:

DEVELOPMENT_TEAM = ABCDE12345;

While the next line does set the correct DEVELOPMENT_TEAM, Xcode only applies that value for device builds (iphoneos). For simulator builds (iphonesimulator) or when the conditional doesn’t match, it falls back to the empty Team ID ("").

Please make this change and let us know if it resolves the issue.

[MatthewJones517]

@archita105 That's only used when you're doing automatic code signing. We're purposefully handling codesigning manually.