Getting error when pasting nodes from a material function

I created a custom material function. For troubleshooting purposes, I want to paste some of the material nodes into another material to play with them. When I try to save it, I get a “Graph is linked to object(s) in external map.” Error.

Here’s the full error:

Can’t save …/…/…/…/…/…/Users/Trev/Documents/Unreal Projects/prj_lamplight_alpha_01/Content/Materials/Material_Functions/NewMaterial.uasset: Graph is linked to object(s) in external map.
External Object(s):

Try to find the chain of references to that object (may take some time)?


I am investigating this issue, but have some questions. Can you reproduce this error in a new asset or project? If so, what are the exact steps that you take? Can you attach you log files as well? They are located in the [PROJECTNAME]/Saved/Logs folder. Any additional information may help.

Here’s the error in the log, also I attached the full log. I’ll try to reproduce this in another project as well as soon as I can.

[2014.05.06-23.35.40:484][191]Cmd: OBJ SAVEPACKAGE PACKAGE="/Game/Materials/slope_blend" FILE="…/…/…/…/…/…/Users/Trev/Documents/Unreal Projects/prj_lamplight_alpha_01/Content/Materials/slope_blend.uasset" SILENT=true
[2014.05.06-23.37.02:039][191]EditorErrors: New page: Save Output
[2014.05.06-23.37.02:039][191]EditorErrors:Warning: Warning Can’t save …/…/…/…/…/…/Users/Trev/Documents/Unreal Projects/prj_lamplight_alpha_01/Content/Materials/slope_blend.uasset: Graph is linked to external private object Unknown

Hey Hyperloop -

If I may clarify one thing, the material function you are copying from is it located in the Engine or Game directory in content? And, if possible could you give us a screenshot of the original Material Function nodes?

Thanks Hyperloop - Eric Ketchum

I am going to close this thread due to lack of activity, but should the problem arise again, please feel free to comment and we will reopen the issue.

Hi, I just encountered the same issue.
But I found out what was giving the problem. It’s not the the copied nodes but the copied comment boxes that give the error.
Btw I’m currently using 4.5. Haven’t tried it in 4.6.

(just posting this so you can reproduce this error more focused, and for other people who are having the same issue. )

So to bypass this. Just copy what you want but after copying delete comment boxes and make new ones.

I confirm this still exists in 4.8 as well