Swarm Agent Light Build error in UE4

Hello guys! We have a problem that we cant manage to solve. We are trying to build a large map with many assets, and the build is crashing before it even begins. The error that appears in the swarm agent is this one:

15:46:47: [Interface:OpenChannel] Error: System.IO.IOException: The process doesnt have Access to the file ‘D:\UnrealEngine-release\Engine\Binaries\DotNET\SwarmCache\AgentStagingArea\v1.E21CD36F0EA8C6C8C5310697C9C7C82EAD680461.mtrlgz’ because it is being used in another process.
en System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
en 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)
en System.IO.FileStream…ctor(String path, FileMode mode, FileAccess access, FileShare share)
en NSwarm.FSwarmInterface.OpenChannel(String ChannelName, EChannelFlags ChannelFlags)
We dont have a clue what this might be. We have even removed the warnings we got in the build. Every day new assets are added to our large map. I dont really know if its an asset thing.
Thank you very much in advance!