I have an old project in UE4.27 I want to switch engines to 5.4.
This project uses some plugins (Advanced Sessions, Simplex Noise, some others) which seem to be preventing me from opening the project in a new engine.
Here are some things I’ve tried:
Right clicking .uproject and switching engine version (gives me a vague error “failed to launch project” or something alike)
Deleting saved and intermediate files
Deleting .sln and regenerating visual studio files
Disabling the plugins and removing the plugins folder before trying the above
Opening a new 5.4 project from the Epic Launcher and attempting to open a copy of the project
Generating VisualStudio project files:
Discovering modules, targets and source code for project…
C:\Users\Jackson\Documents\Unreal Projects\0_Pre2023\EcoRonin 5.4\Plugins\SimplexNoise\SimplexNoise.uplugin: warning: Unknown platform Win32 while parsing allow list for module descriptor SimplexNoise
C:\Users\Jackson\Documents\Unreal Projects\0_Pre2023\EcoRonin 5.4\Plugins\AdvancedSteamSessions\Source\AdvancedSteamSessions\AdvancedSteamSessions.Build.cs(16,105): error CS0117: ‘UnrealTargetPlatform’ does not contain a definition for ‘Win32’
Total execution time: 3.41 seconds
Expecting to find a type to be declared in a target rules named ‘EcoRoninTarget’. This type must derive from the ‘TargetRules’ type defined by UnrealBuildTool.
I’m not a C++ programmer, and I am out of ideas. Any suggestions on how I could get this project to open in 5.4 would be great!
Thanks!
EDIT: I tried a new solution:
Create an empty 5.4 project
Migrate the Content folder of the 4.27 project into the 5.4 project without any of the plugins
I try to open ANY of the assets, and the editor immediately crashes.
Another solution I tried:
Copy the 4.27 project
Remove the plugins and disconnected all missing plugin nodes
Game is playable in editor in 4.27 without the plugins and without errors
Try to switch engine versions to 5.4
Try to launch project and get “Error: Failed to launch editor” with no other explanation!
I also tried: Migrating the playable 4.27 content folder (without any plugins or compile errors) into a clean 5.4 project, and I still can’t open a single blueprint asset in the the 5.4 project without crashing the engine! Everything works fine in 4.27!
Open the two. cs files in the Source folder, and set the DefaultBuildSettings = BuildSettingsVersion.V2; Change to DefaultBuildSettings = BuildSettingsVersion.V5;
Open the plugin folder and delete binaries and intermediate for each plugin
Right click on MyProject.uproject > Switch Unreal Engine version , select 5.4, and then open the project
Generating VisualStudio project files:
Discovering modules, targets and source code for project…
C:\Users\Jackson\Documents\Unreal Projects\0_Pre2023\EcoRonin\ERI Copy 2\Plugins\SimplexNoise\SimplexNoise.uplugin: warning: Unknown platform Win32 while parsing allow list for module descriptor SimplexNoise
C:\Users\Jackson\Documents\Unreal Projects\0_Pre2023\EcoRonin\ERI Copy 2\Plugins\AdvancedSteamSessions\Source\AdvancedSteamSessions\AdvancedSteamSessions.Build.cs(16,105): error CS0117: ‘UnrealTargetPlatform’ does not contain a definition for ‘Win32’
Total execution time: 4.21 seconds
Expecting to find a type to be declared in a target rules named ‘EcoRoninTarget’. This type must derive from the ‘TargetRules’ type defined by UnrealBuildTool.
Ok so it turned out that there were two engine plugins (not project plugins) that were still being used in the project and once I unchecked those I was able to follow the steps and get the project to begin opening.
However once it got to 90 something % the editor crashed:
Even after removing all the plugins and having the game run successfully in 4.27 without them, I still get this message when trying to switch engine versions.
EDIT: I got passed this point by changing the .cs files to V5 rather than V2 like the comment above. Now I can get the project to start opening, but crashes at 96%.
Also, when I migrate the content folder across to a blank 5.4 project I can get it open to the third person demo map but as soon as I try to open a level related to my project or any of the blueprints the editor crashes.
But you are not copying the content directory via Windows but using the Unreal Editor with the “migrate” function? In the editor you also have the “Validate …” and the “Update Redirector …” functions when you right-click on a directory.
Otherwise I would try a new C++ project and start the editor via Visual Studio. In the event of a crash, VS will then show the point in the code that caused the crash and you can then search for solutions.
Perhaps also take an intermediate step with UE5.0.
