Assertion Failed error with 4.27

Development Programming & Scripting
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1

Hey, whenever I load up my project using 4.27 it crashes nearly immediately with the following error:

Assertion failed: Index.IsImport() && ImportMap.IsValidIndex(Index.ToImport()) [File:D:\Build++UE4\Sync\Engine\Source\Runtime\CoreUObject\Public\UObject/Linker.h] [Line: 112]

After that prompt these errors pop up aswell:

UE4Editor_Core
UE4Editor_CoreUObject
UE4Editor_Engine
UE4Editor_UnrealEd
UE4Editor
kernel32
ntdll

I can somewhat fix it, if I delete specific files which makes it open properly. But, said files is important to the game. At first I thought they were corrupted, but when opening an empty project with nothing but the “problem” files , the project is able to launch properly with me also being able to access them fine.
Any help is appreciated I’d really just like to be able to continue working on my project because I have deadlines to meet, trying my best to not have to do multiple months of code over if the only fix is deleting those files.

2

Based on the error message you provided, it seems like there may be an issue with the linker for one of the objects in your project. This could be caused by a number of things, including corrupted files or conflicts with other objects in your project.

  • Try verifying the integrity of your project files: In the Epic Games Launcher, click on the Library tab, then right-click on your project and select Verify. This will check your project files for any corruption or errors and attempt to fix them.
  • Check for conflicts: Make sure there are no conflicting objects in your project. If you recently added a new object, try removing it temporarily to see if the issue goes away. Also, check if there are any duplicate objects or assets with the same name.
  • Try rebuilding the solution: In Visual Studio, go to Build > Rebuild Solution. This will rebuild all of the code files in your project and may resolve any issues with the linker.
3

Screenshot (137)

Dont know if I’m missing something but I’ve never had a verify option for my projects. But, I’ll test out the other things later tonight. Thx for the suggestions.

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4

So first two options didn’t fix it, and as for the third. I don’t use VS much but when I went to builds the only option after that was “Run code analysis on solution” which didn’t seem to do anything. So if there’s a specific file I have to open to be able to do “rebuild solution” let me know.

5

I apologize, I forgot that the button is on the installed Engine Version.
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6

That’s fine, been using fix up redirectors atm on each folder while checking for tags when it crashes, since I seemingly can’t “rebuild solution” in VS. Lmk if I’m missing an option I have to tick for it for rebuild. Can’t find anything online either about rebuild solution missing

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7

Hello. If the issue still persists, you should do the following:

-Open the EpicGames application and select Unreal Engine from there.
-Click on the Library and next to the launch button of the installed version, press the arrow button and select Verify.
-After verification is complete, delete the Binaries, Intermediate, and Saved folders from your project folder.
-Right-click on your {ProjectName}.uproject file and select Generate Visual Studio Projects option.
-Wait until the installation is complete.
-Open the {ProjectName}.sln file in the Project folder with Visual Studio.
-Click on Build -> Rebuild Solution from the top menu.
-Once the build is completed, try opening your project again and build the application.

I solved my issue this way. Hopefully, it will work for you too.

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