Server 2012 R2 SMB Issues Migrating from Server 2008

Hi Experts.
Previous Environment:  Server 2008 Terminal Services on a physical server with Caseware Working Papers 2015 Accounting Software - files were stored on a QNAP NAS.
New Environment:  Server 2012 R2 RDS on a Hyper-V VM with the same Caseware Working Papers 2015 files now on a Server 2012 R2 File Server (also a Hyper-V VM).

We're continuously getting errors in the Caseware application that indicate file corruption. Our thoughts are with the SMB stack and potential issues there. Just wondering what to try and how to even begin troubleshooting this issue.

Thanks for any suggestions.

James ParsonsAsked:
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Did you check the TCP offload settings for the NIC on the new server? It can be a cause of issues sometimew, and needs to be disabled in Hyper-V as well as Windows itself (NIC properties).
James ParsonsAuthor Commented:
Hi masnrock. Just to confirm, TCP Offload should be disabled on the NIC on the new server and inside Hyper-V? Which server should this be the case on? All of them, or just the RDS servers? We were running the environment with some users on the older Terminal Server, but the data on the new 2012 box for a while, and they weren't seeing any issues. That leads me to think that the problem is with the RDS sessions.

Yes, in Hyper-V and the NIC. Might as well do it for RDS servers as well.
James ParsonsAuthor Commented:
As it turns out, the issue was related to SMB Multichannel, a feature of SMB 3.0 introduced in Server 2012. Disabling SMB Multichannel seems to have solved the problem.

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