We are getting smbclient errors, while the errors don't appear to be causing any issues we are getting a fair few of them daily:

Log Name:      Microsoft-Windows-SmbClient/Connectivity
Source:        Microsoft-Windows-SMBClient
Date:          12/02/2015 7:36:55 AM
Event ID:      30803
Task Category: None
Level:         Error
Keywords:      (64)
User:          SYSTEM
Computer:      domainserver.domain.com
Description:
The network connection failed.

Error: {Device Timeout}
The specified I/O operation on %hs was not completed before the time-out period expired.

Server name: pcname
Server address: xxx.xxx.xxx.xxx:445
Connection type: Wsk

Guidance:
This indicates a problem with the underlying network or transport, such as with TCP/IP, and not with SMB. A firewall that blocks port 445 or 5445 can also cause this issue.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-SMBClient" Guid="{988C59C5-0A1C-45B6-A555-0C62276E327D}" />
    <EventID>30803</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x400000000000040</Keywords>
    <TimeCreated SystemTime="2015-02-11T21:06:55.276761800Z" />
    <EventRecordID>1475</EventRecordID>
    <Correlation />
    <Execution ProcessID="4" ThreadID="18400" />
    <Channel>Microsoft-Windows-SmbClient/Connectivity</Channel>
    <Computer>domainserver.domain.com</Computer>
    <Security UserID="S-1-5-18" />
  </System>
  <EventData>
    <Data Name="Reason">4</Data>
    <Data Name="Status">3221225653</Data>
    <Data Name="ServerNameLength">12</Data>
    <Data Name="ServerName">STORE-5461-K</Data>
    <Data Name="AddressLength">16</Data>
    <Data Name="Address">020001BDC0A801500000000000000000</Data>
    <Data Name="ConnectionType">1</Data>
  </EventData>
</Event>

Note: Server Address IP can be random PC on LAN, WAN, printer etc.

As well as the following smb errors when our HyperV server that is hosted on 'domainserver' gets backed up to disk on 'domainserver' using MS backup tool:

Log Name:      Microsoft-Windows-SmbClient/Security
Source:        Microsoft-Windows-SMBClient
Date:          11/02/2015 7:18:16 PM
Event ID:      31010
Task Category: None
Level:         Error
Keywords:      (256)
User:          N/A
Computer:      hypervserver.domain.com
Description:
The SMB client failed to connect to the share.

Error: {Access Denied}
A process has requested access to an object, but has not been granted those access rights.

Path: \hypervserver\f$
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-SMBClient" Guid="{988C59C5-0A1C-45B6-A555-0C62276E327D}" />
    <EventID>31010</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x200000000000100</Keywords>
    <TimeCreated SystemTime="2015-02-11T08:48:16.712649800Z" />
    <EventRecordID>3277</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>Microsoft-Windows-SmbClient/Security</Channel>
    <Computer>hypervserver.domain.com</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="Reason">12</Data>
    <Data Name="Status">3221225506</Data>
    <Data Name="ShareNameLength">10</Data>
    <Data Name="ShareName">\domainserver\f$</Data>
    <Data Name="ObjectNameLength">0</Data>
    <Data Name="ObjectName">
    </Data>
  </EventData>
</Event>

• Edited by NorbertG_TJG Thursday, February 12, 2015 3:42 AM more details

Hi,

The issue could be that you transfer data over SMB by using certain RDMA-capable network adapters, the RDMA connections may fail back to TCP.  You could install update 2919355 to resolve the issue.

Event 30818 RDMA connections fail back to TCP caused by NDK disconnection
http://support.microsoft.com/kb/2925980

Best Regards,

Mandy