Why does windows signtool report packaged .exe as invalid?

Development Platform & Builds
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This is a bug in Unreal Engine due to Epic’s internal deployment process for pre-build UE versions.

Epic signs the Engine\Binaries\Win64\BootstrapPackagedGame-Win64-Shipping.exe
And when you download the pre-build Engine from the launcher this executable comes with Epic’s signature.

However, .rc file of this executable gets altered via “StageBootstrapExecutable” method of “Engine/Source/Programs/AutomationTool/Win/WinPlatform.Automation.cs”

Thus, signtool rightfully complains that signature of the executable is invalid.

Here is the potential solutions:
a. Remove the Epic’s signature via signtool:

  • signtool remove /s “C:\Program Files\Epic Games\UE_5.0\Engine\Binaries\Win64\BootstrapPackagedGame-Win64-Shipping.exe”
  • Rebuild the project
  • Sign the final executable

b. Build the engine from source:

  • “BootstrapPackagedGame-Win64-Shipping.exe” will be unsigned in this case.

c. Fix from Epic:

  • Epic shouldn’t sign “BootstrapPackagedGame-Win64-Shipping.exe” during their deployment process.
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