The location of the client registry entry for opportunistic locking has changed in Windows 2000 from the earlier location in Microsoft Windows NT. In Windows 2000, the registry entry that disables opportunistic locking is:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MRXSmb\Parameters
OplocksDisabled REG_DWORD 0 or 1
Default: 0 (not disabled)
You can also set Windows 2000 to deny the granting of opportunistic locks by setting the following registry entry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters
EnableOplocks REG_DWORD 0 or 1
Default: 1 (true)