Packaging Error: An item with the same key has already been added

In my project I am consistently receiving this error,

“PackagingResults: Error: System.ArgumentException: An item with the same key has already been added.
UATHelper: Packaging (Windows (64-bit)): AutomationTool exiting with ExitCode=1 (Error_Unknown)
UATHelper: Packaging (Windows (64-bit)): BUILD FAILED
PackagingResults: Error: Unknown Error”

I tried every solution from the forums, like deleting saved and intermediate folders, checking the plugins if duplicate, and so on. None of the solution worked for me. Basically, I got stuck about a week.

Using 4.26. Any help welcome. Thanks.

i had the same problem
Could you please check the Plugin folder in your project?
Plugins in Engine and Project can have conflict
if it exist try to delete Plugin folder from the project


Hi, thanks for the reply. I solved that by trying to switch shipping to development! Hope could help

I just had this. The problem was a plugin that had a duplicate in the unreal engine plugins folder. It was an old version that I wasn’t using and I had a newer version that was in the project folder. I deleted the old version from the engine’s plugins folder and now it works perfect. It was for “imposter baker” a plugin that had to be manually pasted to the plugins folder when my project was in ue4, when I switched to ue5 the new version had to be pasted directly into the project folder so I had a hidden duplicate.

Hope that helps someone out there