LowLevelFatalError FilenameToLongPackageName failed to convert

Hello, I am getting the error

“LowLevelFatalError [File:D:\build++UE5\Sync\Engine\Source\Runtime\CoreUObject\Private\Misc\PackageName.cpp] [Line: 772]
FilenameToLongPackageName failed to convert ‘’. The Result would be indistinguishable from using ‘’ as the InFilename.”.

To outline what I have already tried from other forum posts:

  • I checked “Enable support for long paths”
  • I checked the line of code in PackageName.cpp [772] in the engine and set up a return type if it receives an empty string (I still got the same error)
  • I attempted to move my project to the same directory as my UE5 folder, clean build and package from there
  • I deleted all temporary files and re-generated files to build and package

I can set up debug logs to print out the specific file name that is giving the build the issue, but I am unsure where to find those logs in the build file. I also have a funny feeling about where my project files are as the error is in my D:/ drive but my UE5 folder is in my C:/ drive. Any help would be much appreciated, let me know if you need any more info!

  • Another detail, I have a warning to a Data Table that the game cannot find, but I checked all blueprint references and cannot find any reference to a data table type.
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Did you ever find a solution for this? I also have this issue, along with the warning of a Data Table that can’t be found.

Hello, I ended up making sure my project was on my C:// driver under “Unreal Projects” where it’s supposed to be and my engine is on the same drive. The data table I believe I had to right click on the DT in the editor and hit “Copy reference file path” and paste that into the string argument. From there I deleted the two apostrophes on either end and used the path from /game and on if that makes sense.