Sarah,

I addition you can change file (table) attributes as shown in How to change file attributes programmatically FAQ #15763.

>I had a user the other day who had a number of problems, not least because a poorly named file (books.sys) had been made readonly. This vital little file holds the next id for our table so is constantly being updated.
>
>It opened ok, could be read but now that it was readonly the updates couldn't happen and further problems resulted.
>
>Is there a way I can test if the table is opened and not readonly?
>
>thanks in advance
>
>Sarah