Crash when opening a new level

Development Programming & Scripting
1

when I try to create a new level my engine crashes evertime. when I create a new level in another project then it works fine but, not in my actual game. The following is the error. Please help me.
Assertion failed: [File:D:\Build++UE4\Sync\Engine\Source\Editor\UnrealEd\Private\EditorServer.cpp] [Line: 1971] /Game/Levels/MainLevel.MainLevel still around while trying to load new map (Object is not currently rooted)

UE4Editor_Core
UE4Editor_Core
UE4Editor_Core
UE4Editor_Core
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_UnrealEd
UE4Editor_LevelEditor
UE4Editor_LevelEditor
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_Slate
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
UE4Editor_ApplicationCore
user32
user32
UE4Editor_ApplicationCore
UE4Editor
UE4Editor
UE4Editor
UE4Editor
UE4Editor
kernel32
ntdll

2

Hello,

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.

https://epicsupport.force.com/unrealengine/s/

Thanks