Created On: 20 October 2010
Problem:
Windows has its own locking mechanism, called Opportunistic Locking, for files shared in a network environment. This mechanism is enabled by default and can contribute to file errors and performance issues in such an environment.
Resolution:
Disabling Opportunistic Locking on Windows Client PCs
To disable opportunistic locking on a Windows client PC, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\System\\CurrentControlSet\\Services\\MRXSmb\\Parameters OplocksDisabled = 1
Disabling Opportunistic Locking on Windows Servers
To disable opportunistic locking on a Windows server, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters EnableOplocks = 0
Disabling Opportunistic Locking on SMB2
Opportunistic Locking cannot be turned off for SMB2, but you can disable SMB2 itself.
To disable SMB2 on a Windows Server 2008 or Windows Vista PC, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters SMB2 = 0
Once SMB2 is disabled, SMB1 will be used and the methods described above will be applicable in order to disable opportunistic locking for SMB1.
To disable opportunistic locking on a Windows client PC, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\System\\CurrentControlSet\\Services\\MRXSmb\\Parameters OplocksDisabled = 1
Disabling Opportunistic Locking on Windows Servers
To disable opportunistic locking on a Windows server, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters EnableOplocks = 0
Disabling Opportunistic Locking on SMB2
Opportunistic Locking cannot be turned off for SMB2, but you can disable SMB2 itself.
To disable SMB2 on a Windows Server 2008 or Windows Vista PC, change or add the following Registry value:
HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\LanmanServer\\Parameters SMB2 = 0
Once SMB2 is disabled, SMB1 will be used and the methods described above will be applicable in order to disable opportunistic locking for SMB1.
Old KB# 32125
