Problem Getting Swarm Agent Cache Working on External Hard Drive

Hi,

I am trying to set up the Swarm cache on my external hard drive, but I get this error message when I now try to build lighting:

5:36:51 PM: [Interface:OpenChannel] Error: System.IO.IOException:

The process cannot access the file ‘D:\SWARM\AgentStagingArea\v1.C401EA93502AF459DEFCC84349DA1D90F8CAF398.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:\Build++UE4\Sync\Engine\Saved\CsTools\Engine\Source\Editor\SwarmInterface\DotNET\SwarmInterface.cs:line 1604

Any idea what the issue is?

Here are my Swarm settings:

Also any more general guidance on setting up the cache on another drive (Other than just putting in the drive name?)