We ran into an issue with Macs connecting to our file services while attempting an upgrade on a Microsoft Clustering Services File Services on Server 2012R2.
Two 2012R2 Servers/Two 2016 Servers, with the following Roles/Features Installed:
ROLES – File and Storage Services:
- File Server
- DFS Namespaces
- DFS Replication
- File Server Resource Manager
- Failover Clustering
Two Virtual Machines running 2012R2, with Microsoft Clustering Services, with multiple File Server Roles. Everything works with the Macs connecting to these Clustered File Services while running 2012R2. The cluster level is also 2012R2.
However, after adding a 2016 Server into this Microsoft Cluster, and failing over one of the file server roles to it, the Macs can no longer connect to that file server. They receive a message stating:
There was a problem connecting to the server “”. Check the server name or IP address, and then try again. If you continue to have problems, contact your system administrator.
If you migrate the file server role back to a server running 2012R2 the Mac can once again connect.
I plan to come back to this blog to post a more detailed writeup. I was passed on a lot of information that I haven’t seen but I will try to best to explain what I believe is happening.
When a 2016 Server is added to a 2012R2 only cluster, the cluster moves into “Mixed Mode” to allow both Operating Systems to function. Now Microsoft states you should not stay in this mode very long, from what I’ve seen thrown around no more than 4 weeks.
This is hearsay from packet captures but when a Mac tries to connect to the File Services running on 2016 Server while in mixed mode it supposedly connects on SMB 3.1.1, but then something in the network stack wants to downgrade the connection to SMB 2.0, and the Macs cannot follow it and therefore cannot connect to the server.
However, after removing the 2012R2 servers, and then upgrading the Cluster Level to 2016, the Macs can then connect again.
I’m still doing some troubleshooting and this post will be updated.