The world contains invalid actor files. Migration to UE5.1

Hello guys, I have a problem after migrating UE5.0 to UE5.1

The project almost working normally, but there is a warning:

“The world contains invalid actor files. Click the Repair button to repair them.”

image

When I click the repair button, it crashes immediately. And give an error message like that:

Blockquote
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000048
UnrealEditor_SceneOutliner
UnrealEditor_SceneOutliner
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_Slate
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
UnrealEditor_ApplicationCore
user32
user32
InkObj
atlthunk
user32
user32
UnrealEditor_ApplicationCore
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

Do you have any idea, how can I fix this?

Thanks

3 Likes

I have the exact issue. Hopefuly somebody can share solution. Thank you in advance.

1 Like

Try deleting ‘Intermediate’, ‘Saved’, ‘Binaries’ and sln file in your project and recreating the project file by left clicking .uproject and clicking generate project file.
This helps me to figure out this problem

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Thanks for the answer.
The project is based on blueprint, and it didn’t have any binaries folder and sln file.

To generate project files, I created an empty C++ project with the same name and copy its “source” folder to my project. How do add c++ source files to BP project?

It still didn’t generate the file with the following error: " Couldn’t set association for project. Check if file is writable." I realized it because the name of the project folder includes special characters.

After fixing these, I was able to generate project files. I edited uproject file with a text editor and removed plugins, in case they’re the problem. Also, I verified engine files.

Then I tried deleting folders and files you said, then generated project files.

Unfortunately, that “repair errors” button is still there and still it’s crashing when I click it.

Same issue here. The repair button crashes the engine and Visual Studio doesn’t point us in any direction as to what are the “invalid actor files” .
Tried the solution above but that didn’t fix the issue.
Anyone solve this issue?

That issue seems to happen when one or more actors in the scene lose reference during the migration process. It may be due to a plugin that is not present in 5.1.

The tool that is supposed to fix it is definitely broken. The only way I could avoid those warnings for now is getting rid of the content that is not available in 5.1 before the migration process. After migrating it there is no easy way to find, select and delete the broken references from the level.

Do not click this button. It is internally broken.

I’ve debugged this piece of code and it is caused by invalid usage of TUniquePtr inside the it.

Exact location: https://github.com/EpicGames/UnrealEngine/blob/release/Engine/Source/Editor/SceneOutliner/Private/ActorBrowsingMode.cpp#L1127

Summary:

  1. Collect each invalid actor info (raw pointer)
  2. Clear original array of invalid actors (unique pointers clear memory, raw pointers are no longer valid)
  3. Access objects using invalid raw pointers

It seems like there’s another flaw: the actor desc pointer can be nullptr from the beginning, and is later accessed by the code without any checks.

1 Like

Had same error, did some testing, it seems caused by some missing plugin, check you have all plugins enabled for content you use on your map. Hope repair button will be fixed in future update

So I’ve already tried installing the required plugins and even deleting all content from the outliner in my map. However, this has NOT fixed the The world contains invalid actor files. issue for me! (Even though the level outliner appears to be empty in the editor.)
Has anyone found a solution to this issue, that goes beyond checking plugins are installed?

Maybe even a word from Epic on whether or not the crash will be fixed in the next Unreal Update?
Currently this issue is preventing us from upgrading to Unreal Engine 5.1.

One theoretical solution would be to just copy+paste everything from the level outliner to a new level. This solves the issue in our case, but the landscape doesn’t seem to get copied over in a world partitioned level. So this is not really a practical solution afaik.

Experiencing the same problem as everyone else. Has anyone filed a bug report with Epic yet ?

I got this error when I removed the C++ files. It is required to remove Binaries and Intermediate, after recompiling the project in the studio and after opening UE Editor

I fixed it by:
First, recompile the whole project from the button at the bottom right.
Then go:
Content Drawer → Currently loaded world → Right click → Asset Actions → Reload

To not have to do this every time, you can force recompile at startup from:
Edit → Editor Preferences → Search for Force Compile at Startup and enable it.

2 Likes

yeah, that’s the answer. when i up UE to higher-level version, it’s OK

I’m also having this problem. How to solve it? It’s a native project in 5.1 not migrated. It’s so frustrating.

Same here… native 5.1 project. None of the suggestions here are working unfortunately.

Hi, I just followed the instructions to force the Engine To Compile on startup. It did solve the issue, because I was able to detect the missing/broken objects that were lying around in the world (map) => Maybe go this way, it seems to help:

“To not have to do this every time, you can force recompile at startup from:
Edit → Editor Preferences → Search for Force Compile at Startup and enable it.” by m3M0RyHuN73R

Could you help me out here please? Running in to the same problem, but what you have described, i can not find it at all. Since the last update from fortnite, the new season, we seems to have this error. Clicking the repair button does not help. I really have no idea what is causing this. Epic closed the bug report, saying duplicate, but i can not find any solutions for this?