UE4.23.0 - Renaming map with terrain can cause data loss

My game still has a map called ThirdPersonExampleMap because at this point I am unable to rename it. If i attempt to rename the map, this results in massive data loss, where I then have to use git to revert the attempt.

A user without version control or a backup could lose a lot of data due to this, can someone please investigate the cause?

This has been an issue for me since 4.8.

There are three steps to duplicating the issue:

  1. Make a base map with level streaming enabled controlled by blueprints
  2. Make ThirdPersonExampleMap one of the child maps of the base map
  3. Create a large terrain with painted complex texturing on the ThirdPersonExampleMap
  4. Attempt to rename thirdpersonmap by right clicking, choosing rename. You will eventually be met by a raft of errors relating to external packages. When prompted, click YES then CANCEL:


  1. Everything seems fine for now, so go to SAVE ALL
  2. Note that in SAVE ALL, your new map name is NOT shown in the list of objects to save, but the old map name plus BASE are.
  3. Load this new map you renamed by double clicking on it. Initially, this will work.
  4. Switch back to “BASE”.
  5. Your renamed map is gone, with no option to select it in the editor, nor even the old version, which apparently it saved in step 6.


[You can see a youtube video of the bug happening here][3], i managed to duplicate it every time, safe in the knowledge that after each try I could roll back with git.

[This seems to be a related issue from the unreal tournament forums some time ago.][4]

Please note i listed this under 4.23.0 preview as there is no option for 4.23.0 release, this was actually happening in 4.23.0 release.

After further testing it seems that there is a workaround - duplicate the ThirdPersonExampleMap to BaseTerrain, add BaseTerrain to the world and remove ThirdPersonExampleMap from the world, make sure everything looks ok, then remove ThirdPersonMap from disk.

Should this be the way the engine renames the asset, instead of the flawed way it does it now?


We’ve recently made a switch to a new bug reporting method using a more structured form. Please visit the link below for more details and report the issue using the new Bug Submission Form. Feel free to continue to use this thread for community discussion around the issue.



Thanks, i have submitted the bug via that form, is there any way to see outcome or progress of bugs submitted to the salesforce system?

Hi all,

Cannot imagine I still met same issue after 2 years later.

I reply this post because I find a better way:

1、Open the map (blueprint)you can not save;
2、Rename this file.

That’s all!

Having the same problem now, what file should be renamed?

If you operate on your level, open your level, then rename the same level in Unreal Editor.

1 Like