Here’s a bug you will come across when using a subform in datasheet view:

«Property Not Found»

Here is the code that will trigger the criptic message from Access:

Private Sub MyField_BeforeUpdate(Cancel as Integer)

if somecondition = True then

Msgbox «Your message here, usually you can’t save the record because of something»

Cancel = True

end if

End Sub

To fix the issue, replace Cancel = True with:

DoCmd.CancelEvent