breakaway: I see, disabling SMB2/3 may well be the solution for me.

Has anyone here implemented this solution? Due to the size of most deployments most sites are a single server -- usually a 2008 R2 or a SBS with DC role, with DFS for file replication (user profiles etc to datacentre). Just wanted to confirm disabling SMB2/3 woudn't have a detrimental effect on DFS/AD-Related services.

I have used it on at least three sites. two were running the MYOB database on the SBS2008 and SBS2011 servers.  There was no impact to the system for any other services.

But standard best practices apply, set the settings on the servers after hours when no users will be impacted.