Did you try to follow VFP Help recommendation:
"...An optimistic locking conflict has been detected while trying to update a view. Make sure your update key is valid. If you want to commit your changes to the base table(s), call TABLEUPDATE( ) with lForce. This will overwrite the changes made to the base table since the view was last fetched...." ?

>I keep getting "Update Conflict", in a multi-user environment in an industrial plant.
>
>I have three updateable local table views in a database:
>
>1st view: lvProduction_B ===> created from Production.dbf LEFT OUTER JOIN Team.dbf
>
>2nd view: lvProduction_A ===> created from lvProduction_B LEFT OUTER JOIN Employee.dbf
>
>3rd view: lvProduction =====> created from lvProduction_A LEFT OUTER JOIN Skid.dbf
>
>I have two different forms. The first form is the "Production" form and the second is the "Weigh" form. The "Production" form can be only accessed from one workstation and and the "Weigh" form only from another. All databases and tables reside on a shared fileserver.
>
>Both of these forms have a single grid. The "RecordSource" of the grid is "lvProduction" (3rd local view), and the "RecourdSourceType" of the grid is "1 - Alias". Buffering Mode is not set on lvProduction since it is a view.
>
>This is the sequence that I do to reproduce the update conflict.
>
>STEP 1. From the Production form (computer) :
>I add a production item to the grid by APPENDing a new record to the lvProduction local view.
>a TABLEUPDATE() and REQUERY() are issued. (OK)
>
>STEP 2. From the Weigh form (computer):
>The item gets a weight after the previously added record (from the production form) by REPLACING the field nProduction_Weight with a numeric value, gotten from a scale attached to the PC via COM port.
>A TABLEUPDATE() is issued.
>Grid is refreshed. (OK)
>
>STEP 3. From the Production form (computer):
>When I edit that same record to add production/quality control information and when a TABLEUDPATE is issued...Everything is NOT OK.....UPDATE CONFLICT OCCURS! The user then has to press OK...a couple of hundered of times. VFP application shuts down.
>
>This update error has ben lingering on some while and is giving me a major problems. I have been unable to come up with a good solution. I would really appreciate any help.
>
>Thanks to all for everyone's input.