>Jim:
>Q1.
>it is not necessary to set exclusive .T. in multiuser environment?!!?
>

No - if you SET EXCLUSIVE ON, then files opened without the SHARED clause will not be accessible to the second user.

>Q2.
>refer your point 2, if i didn't use pack for delete record, how can VFP delete the marked record for me?!
>

The DELETED() function.

>Q3.
>is any other method that can delete the record from the table, but will not cause the problem (something like disconnection....). and if i only set delete on for the record, will the record appear in an other user in another mechine?!
>

IF you have SET DELETE OFF, yes. The DELETED() status also does not prevent the record from being considered for uniqueness for a candidate or primary key if you don't have FOR NOT DELETED() as a qualifier on the index.