Tech Supoport:

I thought these values (from Cam's message above) were correct for OpLocks being OFF.

... KEY: System\CurrentControlSet\Services\LanmanServer\Parameters
VALUE: EnableOpLocks (=0)
... KEY: System\CurrentControlSet\Services\LanmanWorkStation\Parameters
VALUE: UseOpportunisticLocking (=0)
... KEY: System\CurrentControlSet\Services\MRXSmb\Parameters
VALUE: OplocksDisabled (=1)

Nonetheless, of course, he needs to check all workstations and the server.