Running into a bug in the Windows install. This gets repeated over and over in the event logs:
caller=level.go:63 level=info caller=extension.go:494 err="sending string logs: writing logs: transport error sending logs: rpc error: code = Internal desc = grpc: error while marshaling: proto: field \"kolide.agent.LogCollection.Log.Data\" contains invalid UTF-8"
caller=level.go:63 level=info caller=publish_logs.go:157 method=PublishLogs uuid=d121472b-e355-4c07-954c-4422799c88f4 logType=string log_count=707 message= errcode= reauth=false err="rpc error: code = Internal desc = grpc: error while marshaling: proto: field \"kolide.agent.LogCollection.Log.Data\" contains invalid UTF-8" took=3.0001ms
Appears to have been fixed in 4.3 and newer releases of osquery