Externally referenced error, perforce server

Me and my friend are working on a project together using a perforce server. Last night we decided to change the project to build from source. But when we downloaded the source for the UE4 w/ substance plugin 4.11, it instead downloaded the 4.12. Now the issue is that we have built it from source, but are now getting the “Externally referenced” error on static meshes, also we have some broken particle systems. Now my question is this. Since with the normal solution for the externally referenced is to rename the folder after doing a “run from copy” from within the ue4 launcher, and since we did not do this option and accidentally updated the engine from outside the launcher, how would we go about fixing this? Or would it be best to start another project and just import everything back into the new project?

Hello noosence,

The importing would most likely be the easiest process. Do you still have access to the original project without the externally referenced errors? Was any of this backed up on Perforce prior to this new editor version coming into play? Have you also put your engine version into Perforce or is it only your project?

Hi there,

Rather than changing the folder name and back again, there is a better way to fix this that will always work.

Open up your project folder in Windows and navigate to:


and open the file named “Engine.ini” with a text editor.

Go through the “[Core.System]” section where all of the filepaths are located and make sure they point to the correct location for your system. If there are any duplicates, remove them.

As an example, I have a project with a plugin that I keep on my G:\ drive under G:\412\OceanProject, and it contains my OceanPlugin, this is how mine is set up:


Yours should look similar, with a different file path and the Substance plugin instead.

I have had the externally referenced issue quite a few times as I upgrade the project to new versions often, and each time it adds additional “Paths” values with old file paths. That’s all this issue really is, there are no problems with your assets. The issue only occurs around 10% of the time, which isn’t a big deal really, but happens more often when you change the file path before upgrading.

Hope that helps, let me know if you need any more info. =)