This sounds like a Local Master Browser issue.  There can be only ONE Local Master for the Network.  The Local Master Browser is a DNS like server for the SMB network and is determined by an 'election among the computers on the SBM network.  The entire process takes place in the background and has a very low priority.  It can take many, many  minutes to resolve a a network.  For that reason, it is best if you have your unRAID server end up as the Local Master.  "Settings"  >>>  "SBM"  &