Light baking not working due to swarm error...

Hello all, if this is in the wrong section, I apologize…didn’t know where else to post. I recently upgraded my project from 4.7 to 4.9. I cannot do a lightbake anymore. Swarm editor fails to kick off. I’ve created a new project in 4.9 and that bakes fine, so it is something sitting inside of my project from 4.7 that its complaining about. Here is the swarm log file…

4:20:29 PM: [Interface:TryOpenConnection] Local connection established
4:20:29 PM: [Job] Accepted Job 19F4C7AB-4A71F7C4-959157A3-489D32D9
4:20:29 PM: [MaintainConnections] Local connection has closed (62B94CCF)
4:20:29 PM: [MaintainConnections] Removed connection 62B94CCF
4:20:31 PM: [Interface:OpenChannel] Error: System.IO.IOException: The process cannot access the file ‘D:\Program Files\Unreal Cache Data\4.9\AgentStagingArea\8487AD2E5DBA413C81373D29B2915895.ED513CE8425708179DEC92BA8C0AD683.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

I’m unsure of how to track down the offending material or texture if that is what this is referencing -------> 8487AD2E5DBA413C81373D29B2915895.ED513CE8425708179DEC92BA8C0AD683.mtrlgz

Thank you for any and all help I can get on this…