Hi Alessio.

=SEEK(THIS.VALUE,'MyTable','MyIdx')

SEEK() is a function that returns .T. if it finds the record and .F. it it does not. Why are you throwing away the return value? You would be much better off to amend your code as follows:

IF SEEK( This.Value, 'MyTable', 'MyIdx' )
  *** Do what you need to do if the record is found
ELSE
  *** Record not found
ENDIF