[UE 5.4 iOS] Unknown Cook Failure During Packaging – App Store Also Requires iOS 18 SDK

Development Programming & Scripting
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Hi everyone,

I’m trying to package my iOS game project in Unreal Engine 5.4 using a remote Mac build server (via SSH). The build step completes successfully, but the process fails during the cook stage with the error:

AutomationTool exiting with ExitCode=25 (Error_UnknownCookFailure)

The log doesn’t clearly indicate the root cause, even though all assets and plugins appear to load correctly. Here’s a summary of my setup:

  • UE Version: 5.4 (Windows host)
  • Remote Mac: Xcode 15.2
  • Target: iOS (Shipping config, Distribution enabled)
  • Plugin used: BlueprintHttp (marked with PrecompileForTargets = PrecompileTargetsType.Any in its Build.cs)

:paperclip: I also noticed this message in logs:

Missing precompiled manifest for 'BlueprintHttp'

Despite setting PrecompileForTargets in the module, the issue persists.

:red_question_mark:Questions:

  1. What can cause Error_UnknownCookFailure during the cook step if the build finishes fine?
  2. Is there a way to properly include the BlueprintHttp plugin for iOS shipping builds?
  3. Are there known limitations in UE 5.4 regarding Xcode 16 or iOS 18 SDK support?

Thanks in advance for any suggestions or pointers!
Log.txt (53.8 KB)

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Hello there @Kris1402!

This is quite a tricky scenario you are encountering. After checking your log, no clear cultrip is present for Error_UnknownCookFailure. The most likely cause is a conflict with either plugin BlueprintHttp, or your xcode 16 setup. Let’s cover the following:

  • Ensure the plugin is being called from your .uproject file
  • SupportedTargetPlatforms": [“IOS”] should be set at BlueprintHttp.uplugin
  • If the plugin is properly compiled, check your Binaries folder for its related file
  • UE 5.4 support is limited to Xcode 15.x and iOS 17.x SDK at the moment, consider downgrading for your test
  • Finally, there’s an extended log available, as seen here:

Cook failed.
(see C:\Users\User\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_5.4\Log.txt for full exception trace)

Please share the contents of that log here, as we can find a more specific error.