# I can't cook/package my game, and I can't really find the problem from the only 1 error.

**URL:** <https://forums.unrealengine.com/t/i-cant-cook-package-my-game-and-i-cant-really-find-the-problem-from-the-only-1-error/2659649>\
**Category:** Programming & Scripting\
**Tags:** unreal-engine, crash, bug-report, question, Blueprint\
**Created:** [September 25, 2025, 3:43am UTC](https://forums.unrealengine.com/t/i-cant-cook-package-my-game-and-i-cant-really-find-the-problem-from-the-only-1-error/2659649 "2025-09-25T03:43:37Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![BRGEzedeRocco](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/brgezederocco/32/1216890_2.png) [@BRGEzedeRocco](https://forums.unrealengine.com/u/BRGEzedeRocco)\
**Post date:** [September 25, 2025, 4:52pm UTC](https://forums.unrealengine.com/t/i-cant-cook-package-my-game-and-i-cant-really-find-the-problem-from-the-only-1-error/2659649/2 "2025-09-25T16:52:42Z")

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Hi @SteveLosive ,  
I’ve been digging around the Unreal forums and found a few similar cases, maybe one of these solutions could help:

People suggest checking struct variables and using **Refresh All Nodes** in the affected Blueprints

> [@Packaging error due to Unknown Structure ?](https://forums.unrealengine.com/t/packaging-error-due-to-unknown-structure/1771123):
>
> Hey ! I’ve been trying to package my game but unfortunately an error has been coming up : UATHelper: Packaging (Windows): LogInit: Display: LogProperty: Error: FStructProperty::Serialize Loading: Property ‘StructProperty /Game/Inventory/Items/BP\_TestActor.BP\_TestActor\_C:LookAt:CallFunc\_GetDataTableRowFromName\_OutRow’. Unknown structure. UATHelper: Packaging (Windows): LogInit: Display: LogProperty: Error: FStructProperty::Serialize Loading: Property ‘StructProperty /Game/Inventory/UI/WBP\_Drag…

In this post they fixed it by renaming the struct variable, recompiling and saving, or even recreating the struct from scratch

> [@Unknown structure Error When Cook](https://forums.unrealengine.com/t/unknown-structure-error-when-cook/339325/11?page=3):
>
> I just encounter the same problem,and i googled it , i try to use a lot of methods, but it has not been resolved. at last , i renamed the struct. and build the project again. it was sucessed! you can try it.

others solved it by opening the Blueprints that reference the struct, running Refresh All Nodes, and compiling.

> [@Unknown Structure Error](https://forums.unrealengine.com/t/unknown-structure-error/2238831):
>
> Hi, When I try to package my project I get lots of unknown structure errors coming from something with data table row out rows. I don’t get any errors during runtime before packaging and I didn’t get these errors before upgrading the engine version (from 5.4 to 5.5). I can also tell the the path mentioned in the error is wrong, for example: “LogProperty: Error: FStructProperty::Serialize Loading: Property ‘StructProperty /Game/UI/Asset/UI\_Asset\_Widget.UI\_Asset\_Widget\_C:PopulateVariationBox:Ca…

And lastly, this page explains why the error happens and the common steps to resolve it

> **[Unreal Engine Tips: Fixing "Unknown structure" Packaging Error](https://unrealpossibilities.blogspot.com/2021/01/unreal-engine-tips-fixing-unknown.html)**
>
> A blog about video games & game design.

Hope it helps!

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