Can't save umap. Graph is linked to object in external map

[GenericNickname7]

Hi,

I can’t duplicate a certain map in a project. On attempt to save the newly dublicated map - this error pops-up:

Can't save umap graph is linked to object BlueprintGeneratedClass (unknown property in external map)

Please help

Thanks

[SupportiveEntity]

Hey there @GenericNickname7! I’ve seen a thread on this issue before, however I’ve never experienced it myself. So here’s a couple of resources that might have an answer!

Can't save due to "Graph is linked to external private object"

Dear community, I have developed a little blueprint function library class that when used it causes the editor to not be able to save: [40519-message.png] The code below is a blueprint function call: UCLASS() class TESTPROJ_API UMyBlueprintFunctionLibrary : public UBlueprintFunctionLibrary { GENERATED_BODY() public: UFUNCTION(BlueprintCallable, Category = "VictoryBPLibrary") static UFlowerObject* CreateFlowerObject(); }; The “can’t save” problem starts as soon as I set the return value…

Can't save because graph is linked to external object?

One of your blueprints has corrupted reference. Create backup now, before you change anything. And in future do daily backups. When you have backup you need to find culprit blueprint (or actor). Fastest finding method for such stuff is bisection. Ie. you delete half of actors in scene and see if unreal still crashes. Thenb you know in which half of actors corrupted one is. And you continue until you find that one crashing everything. Yes restoring from backups is slow, so consider getting SSD f…

Please let me know if either of these present the answer for you!

[GenericNickname7]

Hi @SupportiveEntity,

Thank you a lot for your help. I familiarized myself with the topics and tried following some of the advices.

What has been tried so far:

• Fixed-up references for the content folder

• Deleted all actors from the map and all level blueprint content. Unfortunately the issue still persists.
  Also, the corrupted versions of the level seem to create 2 level blueprints - packaging gives this error: "UATHelper: Packaging (Windows): LogInit: Display: LogOutputDevice: Error: Detected the creation of more than one LevelScriptActor (/Game/Maps/GamePlayLevel.GamePlayLevel:PersistentLevel.GamePlayLevel_C_4, /Game/Maps/GamePlayLevel.GamePlayLevel:PersistentLevel.GamePlayLevel_C_1) within the same outer. This can lead to duplicate level blueprint operations during play."

• Tried deleting all new blueprints and any new additions the old ones

• I tried substituting the umap with back ups - the recent ones give the same result, the only one that works is 2 weeks old. But it’s at least some good news

[GenericNickname7]

Solution:
Copied all actors from the corrupted map into the emptied back-up map. In case if anyone has the same problem and you didn’t make backups - you can find some in the Saved/Autosaves folder.

In order to copy the blueprint level content and avoid the “failed to save error” - paste the copied content into a notepad and replace the old name level with the new one and recreate references/events for renamed actors in level bp

For example

EventOwner=TriggerBox'"/Game//Maps/GamePlayLevel.GamePlayLevel:PersistentLevel.TriggerBox_1"'EventReference=(MemberParent=Package'"/Script/Engine"',MemberName="ActorBeginOverlapSignature__DelegateSignature")
   bInternalEvent=True

→

EventOwner=TriggerBox'"/Game//Maps/GamePlayLevel1.GamePlayLevel1:PersistentLevel.TriggerBox_1"'EventReference=(MemberParent=Package'"/Script/Engine"',MemberName="ActorBeginOverlapSignature__DelegateSignature")
   bInternalEvent=True

[ductrungg_ADH]

The cause is your code using hard reference to object in another level or level streaming. And this code will run from Construction Script or Pre Construct.
Solution is changing Hard reference to Soft reference.