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4.22 UnrealHeaderTool getting called every build, even if there are no changes

Development Discussion C++ Gameplay Programming
#1

I just installed 4.22, and UnrealHeaderTool is being called every time I build, even if it’s just a CPP change or even if there is no change at all. This happens in any project I try, including new projects. I tried both VS 2017 and VS 2019, same result. Is anyone else having the same problem?

Here’s the output from a build with no changes:

1>------ Skipped Build: Project: UE4, Configuration: BuiltWithUnrealBuildTool Win32 ------
1>Project not selected to build for this solution configuration
2>------ Build started: Project: Realms, Configuration: Development_Editor x64 ------
2>Parsing headers for RealmsEditor
2> Running UnrealHeaderTool “C:\proj\RealmsUnreal\Realms\Realms.uproject” “C:\proj\RealmsUnreal\Realms\Intermediate\Build\Win64\RealmsEditor\Development\RealmsEditor.uhtmanifest” -LogCmds=“loginit warning, logexit warning, logdatabase error” -Unattended -WarningsAsErrors -installed
2>Reflection code generated for RealmsEditor in 8.2522749 seconds
2>Target is up to date
2>Total execution time: 9.38 seconds
========== Build: 1 succeeded, 0 failed, 0 up-to-date, 1 skipped ==========

#2

I was having the same issue. I’ve fixed this by opening the following file in a text editor and saving over itself, giving it a newer last modified timestamp:

UE_4.22\Engine\Binaries\Win64\UnrealHeaderTool.target

Build again, UHT may run once, then following that the issue should be gone - UHT will only run if it actually needs to.

Hope this helps.

#3

Thanks, this fixed it for me! You’re a legend.

#4

I though it’s normal for UHT to be run every time, your discovery is groundbraking!

Epic team should be aware of this and do a fix, I’m running UE4.23 and this problem persists since ever.

#5

This is fantastic. I thought I had to wait every single time. I don’t even want to think about how many hours this cost me.

#6

I have created a bug report and will let you guys know when I receive a response. I’m hoping this gets fixed soon. Just think of all the time everyone is losing to this simple glitch. I didn’t even know that UHT didn’t have to run every single time, I was waiting 10 seconds extra on every build for months!

#7

Do you have a link to the report? Did you manage to repro this in a minimal project/example? If so, please send me the details if not here.

#8

No, I used the new reporting system. I got an email saying that they will get back to me when there is a report filed.

To reproduce, just install UE4 from the launcher and compile a new C++ project. It will rerun UHT every time on every file regardless of what has changed.

#9

@CoolOppo any updates?

I had this issue on 4.23 and stumbled upon this thread which fixed it, thanks a lot! @lpx90

#10

@CoolOppo, I second the update request - did you ever get a link to the report?

#11

I did what you said, then selected a “rebuild” build in visual studio code and now it runs only when it needs to. Thank you very much for this, the issue still happens in 4.24

#12

In 4.24 is work

#13

You deserve the title: LEGEND.
This issue has held me back from investing time to learn UE4 for over 2 years now.
But I eventually decided to go through pain of waiting at least 20s for every build.
This fix makes my build times only 2s max. Ground breaking
With this discovery I’ve just falling more in love with UE4.
Thanks, Thanks, Thanks Big time.

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#14

I just had to reply.

This occurred to me just now because my Windows clock was set wrong (in the future) and I corrected it.

Next thing I knew, my UE4 project builds would infinitely repeat like described here.

I opened and saved over the UnrealHeaderTool.target file as described and that fixed it.

Thank you!

#15

I’m using Visual Studio 2019 on Windows, so I don’t have [FONT=Lucida Sans Unicode]UE_4.22\Engine\Binaries\Win64\UnrealHeaderTool.target in my project directory.

I did find this issue Unreal Engine Issues and Bug Tracker (UE-73197), which says the fix was targeted for 4.23. I’m going through the Udemy course and currently using 4.22 so I haven’t tried this with a newer version.

#16

I am on 4.25.3 and Visual Studio 2017. What I did is follow this in thread

Steps:

  1. You need to create a file (if it doesn’t exist) - C:\Users<your user>\Documents\Unreal Engine\UnrealBuildTool\BuildConfiguration.xml
  2. Paste the following in to the file above:
    Code:

<?xml version=“1.0” encoding=“utf-8”?>
<Configuration xmlns=“https://www.unrealengine.com/BuildConfiguration”>
<BuildConfiguration>
<bUseUnityBuild>false</bUseUnityBuild>
<MinFilesUsingPrecompiledHeader>1</MinFilesUsingPrecompiledHeader>
</BuildConfiguration>
</Configuration>

I hope that helps. The first build always takes about 4 minutes, but consecutive builds only take a few seconds.