Unreal Engine Tips: Fixing "Unknown structure" Packaging Error

Lately, I've been doing some freelance work on the side for some of my UE4 marketplace customers who required custom modifications for the blueprint templates. And one of these projects has a heavy focus on data-driven design through the use of Structures, Data Tables, Data Assets, etc. Without going into specifics, the advantage of doing so is essentially to enable the customer to make changes to the project mostly through data without tinkering with blueprint logic.

While working on this project, I recently had to make some changes to a Structure which was being used across a lot of blueprints. After doing some testing, everything seemed to be working fine, with no compiler errors or gameplay crashes. So I decided to wrap it up and package the project, but then the packaging process failed and threw a whole bunch of "Unknown structure" errors. And it had to do with the edited structure.

Granted the errors show the blueprints that contain this structure, but disconnecting & reconnecting every single one of those "Break Struct" nodes would have been quite time consuming. However, thankfully I stumbled upon an option under the blueprints menu that made this process a whole lot smoother.

Fixing the errors still does require going to each of the listed blueprints, but instead of going to each struct related node, you can essentially go to the File option in the top menu, and select Refresh All nodes.

Compile & save, and then do the same for all of the required blueprints. And that's it. If you try packaging the project again, there should be no "Unknown structure" errors putting a halt to the process anymore.

This simple solution helped me save a decent chunk of time that would have been otherwise spent doing the same repetitive task across several blueprints. So I figured I'll share this information here. Maybe, it'll save you some time in the future.