>>I'm thinking you got struck by grid reconstruction problem. When do you create your cursor and do you re-create it in the life of the form?
>
>I don't think the problem has to do with the cursor. It is something to do with the grid and how some properties of the grid or the Memo field columns work.

What is the ControlSource for the column in question?

See also Why non read-only grid behaves as read-only FAQ #25144 for related info about possible problem.