iShared Copy Issue with Vista Client

Solutions ID:    KB3594
Version:    3.0
Status:    Published
Published date:    12/10/2009
Updated:    03/19/2010

Problem Description

Testing done with copying large files between Windows Vista and Windows Server 2008, and then Vista to Windows 2003, have shown that by using SMB 2.0 the file copying was, in averege, 2 times faster than with older operating systems.

However, while SMB 2.0 seems to do a good job if BOTH client and server OSs support it, in some cases it will slow things down. The reason for this is that the version of SMB used for file sharing is determined during the SMB session negotiation. If both the client and server support SMB 2.0, then SMB 2.0 is selected during the initial negotiation. However, if they don't both support it, SMB 1.0 will be used to in order to preserve backwards compatibility.

The SMB protocol version to be used for file operations is decided during the negotiation phase. During the negotiation phase, a Windows Vista client advertises to the server that it can understand the new SMB 2.0 protocol. If the server (Windows Server 2008 or otherwise) understands SMB 2.0, then SMB 2.0 is chosen for subsequent communication. Otherwise the client and server use SMB 1.0.

iShared appliances run on Windows 2003 platform; hence SMB 2.0 does not apply.  Simultaneous copy of the same file with two or more Vista client machines across the WAN may show problems.


To resolve this issue, OpLocks (opportunistic locks) will need to be disabled on the Vista client machine.  Customers are required to run the commands as an administrator.  For registry changes, please perform a back up of your registry before making any changes.

To disable oplocks on Vista Client, perform the following command:

sc config lanmanworkstation depend= bowser/mrxsmb10/nsi
sc config mrxsmb20 start= disabled

To enable back oplocks on Vista client, perform the following commands:

sc config lanmanworkstation depend= bowser/mrxsmb10/mrxsmb20/nsi
sc config mrxsmb20 start= auto

To disable oplocks On Windows 2008:


Perform the following registry change:

  1. Run "regedit" on Windows Server 2008 based computer.
  2. Expand and locate the sub tree as follows. HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters
  3. Add a new REG_DWORD key with the name of "Smb2" (without quotation mark) Value name: Smb2
  • Value type: REG_DWORD
  • 0 = disabled
  • 1 = enabled
  1. Set the value to 0 to disable SMB 2.0, or set it to 1 to re-enable SMB 2.0.
  2. Reboot the server.  

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