Lighting build failure, swarmagent kick off

Hi,

I checked with many other links about this issue and nothing solve my problem.

My scene was originally built in 4.8 and recently i upgraded to 4.10 with additional features and assets. in the early stage, I am able to build lightning without problem.

only when I almost complete my project, the build light seen not working suddenly.

Need help on this to solve as I have too many objects in my scene to move to a new scene.

Thanks in advance.

btw, here is the log from swarmagent.

9:49:19 AM: Starting up SwarmAgent …

9:49:19 AM: … registering SwarmAgent with remoting service

9:49:19 AM: … registering SwarmAgent network channels

9:49:19 AM: … initializing SwarmAgent

9:49:19 AM: … certificate check has failed

9:49:19 AM: … initializing cache

9:49:19 AM: … using cache folder ‘C:/Users//AppData/Local/UnrealEngine/4.10/Saved/Swarm\SwarmCache’

9:49:19 AM: … recreating SwarmAgent cache staging area

9:49:19 AM: … initializing connection to SwarmCoordinator

9:49:19 AM: … using SwarmCoordinator on RENDER-01

9:49:21 AM: … SwarmCoordinator failed to be initialized

9:49:21 AM: … initializing local performance monitoring subsystem

9:49:21 AM: … initialization successful, SwarmAgent now running

9:49:21 AM: [Interface:TryOpenConnection] Local connection established

9:49:22 AM: [Job] Accepted Job 795C9FCB-40EA4A95-138C0EA1-D92B2179

9:49:23 AM: [Interface:OpenChannel] Error: System.IO.IOException: The process cannot access the file ‘C:\Users\AppData\Local\UnrealEngine\4.10\Saved\Swarm\SwarmCache\AgentStagingArea\8487AD2E5DBA413C81373D29B2915895.90341AF9445E954F329A35886BE01F00.mtrlgz’ because it is being used by another process.

at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)

at System.IO.FileStream…ctor(String path, FileMode mode, FileAccess access, FileShare share)

at NSwarm.FSwarmInterface.OpenChannel(String ChannelName, EChannelFlags ChannelFlags) in D:\Perforce\Epic\UE4\Engine\Source\Editor\SwarmInterface\DotNET\SwarmInterface.cs:line 1590