UE4光照构建失败 Lighting build failed. Swarm failed to kick off

今天遇到个光照构建失败的情况，检查后确定场景中灯光没有问题。查找资料后可通过以下三个步骤解决：

1. Delete the stuff in this folder (or equivalent location – wherever your engine is installed.)

           E:\UnrealEngine-4.24\Engine\Saved\Swarm\SwarmCache

    2. Delete all the stuff in this folder (or equivalent for your engine version.)

           C:\Users\YOURWindowsUser\AppData\Local\UnrealEngine\4.24  （如果没有这个文件夹可以此步骤可略去）

     3. Open the Project.sln file ，Build UnrealLightmass. 

 Once this is done, run the editor and you should be able to build your levels again.