Issue with UE 5.3 and C++

Development Programming & Scripting
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1

Whenever I try to create a UE 5.3 project or upgrade an existing project, the C++ folder fails to appear, I can’t compile the project, and nothing I do can fix this. Everything works perfectly fine on 5.1 and 5.2, so I decided to wait for some updates to 5.3 but this is still an issue.

When I try to generate project files it fails and I get this:

at Microsoft.Win32.SafeHandles.SafeFileHandle.CreateFile(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options)
   at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String fullPath, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize)
   at System.IO.Strategies.OSFileStreamStrategy..ctor(String path, FileMode mode, FileAccess access, FileShare share, FileOptions options, Int64 preallocationSize)
   at System.IO.Strategies.FileStreamHelpers.ChooseStrategy(FileStream fileStream, String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, Int64 preallocationSize)
   at System.IO.File.Open(String path, FileMode mode, FileAccess access, FileShare share)
   at EpicGames.Core.FileReference.Open(FileReference location, FileMode mode, FileAccess access, FileShare share) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\Shared\EpicGames.Core\FileReference.cs:line 432
   at UnrealBuildTool.ProjectFileGenerator.CreateProjectPropsFile(FileReference PropsFile) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\ProjectFiles\ProjectFileGenerator.cs:line 587
   at UnrealBuildTool.ProjectFileGenerator.AddRulesModules(RulesFileType RulesFileType, String ProgramSubDirectory, List`1 AddedProjectFiles, List`1 UnrealProjectFiles, PrimaryProjectFolder RootFolder, PrimaryProjectFolder ProgramsFolder, ILogger Logger) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\ProjectFiles\ProjectFileGenerator.cs:line 540
   at UnrealBuildTool.ProjectFileGenerator.GenerateProjectFiles(PlatformProjectGeneratorCollection PlatformProjectGenerators, String[] Arguments, Boolean bCacheDataForEditor, ILogger Logger) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\ProjectFiles\ProjectFileGenerator.cs:line 1239
   at UnrealBuildTool.GenerateProjectFilesMode.ExecuteAsync(CommandLineArguments Arguments, ILogger Logger) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Modes\GenerateProjectFilesMode.cs:line 65
   at UnrealBuildTool.UnrealBuildTool.Main(String[] ArgumentsArray) in D:\build\++UE5\Sync\Engine\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\UnrealBuildTool.cs:line 659

Any suggestions?

2

Seems to be a permissions issue that I can’t solve.

When I try to build the project in VS I get this error:

"CS0016 Could not write to output file ‘C:\Program Files\Unreal\UE_5.3\Engine\Binaries\DotNET\UnrealBuildTool\UnrealBuildTool.xml’ "

I also finally noticed I could scroll up on the original error and found it’s also an access exception issue:

“Unhandled exception: System.UnauthorizedAccessException: Access to the path ‘C:\Program Files\Unreal\UE_5.3\Engine\Plugins\ScriptPlugin\Source\ScriptGeneratorUbtPlugin\ScriptGeneratorUbtPlugin.ubtplugin.csproj.props’ is denied.”

Everything run as admin, even turned off read-only and changed permissions on all the files to be completely open, still getting these errors.

Again, this is only a 5.3 issue. Everything works perfecting on previous versions.

3

are these engine versions all installed from the Epic Games Launcher, or are any of them compiled from source (I presume that because there is mention of Access Permissions that these are EGL Engine installs)

are all these versions of the Engine binaries in the similar relative locations like D:\*\UE_5.1, D:\*\UE_5.2, and D:\*\UE_5.3 where the “*” is the same between all of them

are you sure that you have the most recent IDE with compatibility to Unreal set up for 5.3?

if say you created a 5.3 C++ project and try to open it would this occur at that point?

could you try Migrating the 5.2 project into a 5.3 blank project which should bring the C++ along? (as long as they are being used in the project, and on rare occurrences raw C++ might need to be manually added if they are not in files for UObject classes already)

4

They’re all in the same location, yeah. Same everything.

I’m having this problem even opening a new, blank 5.3 project too, yes.

The C++ folder for the game, even a new blank one, doesn’t even show up even though it’s checked and the engine C++ folder does. Generating files causes an error, building from IDE runs into that other error, neither of these issues occur in 5.1 or 5.2 projects. Everything is running as admin.

5

can you create a blueprints project in 5.3 does that work?

if you can create a Blueprints project try adding a C++ class and see if that functions?
if you can then see if you can close the project, generate the Visual Studio files, and Launch the project.

in the Epic Games Launcher → Unreal Engine → Library: on the tile for 5.3 there is a drop down arrow is “Verify” a clickable option in that menu? (this may take maybe 1/5th the time it took to install the engine in the first place)

6

Yeah, I don’t get any errors or anything from UE itself. Just can’t compile or build.

I’ve said multiple times already that I can’t generate files and the error codes associated.

And I did already try verifying. It verified without issue.

7

Any resolution to this issue ? I started facing this issue when I restored the back up of engine folder. deleted the project files and try to re generate project files. The exact same error. the access to the path C:\Program Files\Unreal\UE_5.3\Engine\Plugins\ScriptPlugin\Source\ScriptGeneratorUbtPlugin\ScriptGeneratorUbtPlugin.ubtplugin.csproj.props seems just fine.