Anyone know why I can't copy my level

UE 4.23

I have seen some posts on this but all of them are old and/or do not have real answers, at least the ones that I have found.

I was given an UE4 project that had a level, called MM level, that seems to be a copy of another level, called forest. No matter what I do I cannot duplicate MM level. I tried duplicating, save current as, copying all the assets and pasting in blank project. And to no prevail. I was told that level cannot be open while doing any of these and so I tried opening a totally different level and that didnt work. I tried creating a new blank level and tried duplicating, save as and even the copy/paste techniques again and still to no prevail.

I even tried to change the class settings of the level to generate the abstract class and still did not work. However I can duplicate the original level, Forest. But the levels, MM and Forest, at this point are vastly different and need to make a copy of the MM level.

I should mention that the editor crashes upon doing any of these. The only times I get any window prior to crashing is when I try to ‘save current as’ only with the forest level. The window that I get says:

The asset ‘/Game/TheForest/Maps/Demonstration_02/deleteme’ (deleteme.umap) failed to save.

Cancel: Stop saving all assets and return to the editor.

Retry: Attempt to save the asset again.

Continue: Skip saving this asset only.

I hit continue and get:

The following assets failed to save correctly:
/Game/TheForest/Maps/Demonstration_02/[my duplicated level]

I hit ok and get:

Can’t save [mylevel.umap]: Graph is linked to object(s) in external map.
External Object(s):
LandscapeMaterialInstanceConstant_432
LandscapeMaterialInstanceConstant_436
LandscapeMaterialInstanceConstant_492
LandscapeMaterialInstanceConstant_496
LandscapeMaterialInstanceConstant_500

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

I click yes the level is copied but I am met with

Does anyone have any ideas as to what I could be doing wrong? I presume that the LandscapeMaterialInstanceConstants are the issue here but I don’t know what to do to fix this.

Any help would be great.

Thank you for your response! Unfortunately this didn’t work. I had the project closed and duplicated the scene in the window explorer but when i opened the project it just refused to acknowledge the new map.

I just want to clarify when I say it refused to acknowledge the new map I mean it didn’t show in the content browser.

Have you tried just copying the umap file from the windows explorer?

Hmmm… ok something that DEFFO will work is copying the project in the explorer.

If you need to, you can make a new project and migrate just the level to that project ( that way you only get what you need ).

You can then either use the new project to get a grip on this level, or you can copy the project in the windows explorer…

Have you tried to FixUpRedirectors before trying to make a copy of it?