In addition to what Bob recommended, you could try a lock loop instead of a single attempt:

SET REPROCESS TO 0 && indefinite, I will tell it when to stop manually
lntimes=0
DO WHILE !LOCK() .and. lntime<100000
    ?LOCK()
ENDDO
SET REPROCESS TO 1
IF !RLOCK()
   WAIT WINDOW "could not lock record"
   *Error locking record, backout or try again later...
ELSE
   WAIT WINDOW "Successful record lock"
   *Save changes
ENDIF
UNLOCK
SET REPROCESS TO 0

>Hi,
>I am using free table (buffering - 5) in my multiuser application. It is a simple customer data entry app.
>Also, I am using vfp wizard to generate the data entry form.
>
>I face problem of "RECORD IS USED BY ANOTHER USER" when the baseclass try to RLOCK(). It occured when 2 users try to add 2 different records at the same time. Once the 1st user add the record successfully, the 2nd user will get the error.
>However, if I try to debug it, browse the table and re-try the RLOCK() again then it will sucessfully. Any ideas?
>
>Why the "new" record could be locked while other user add another?
>
>Pls help!!
>
>Thank you