Kevin,

>If I Detach a cursor from a CA, can I then later Attach it again
>and issue TABLEUPDATE()?

Works for me.

>My testing shows that I cannot update changes, but I wanted to verify
>that.

You might need to be sure that the CursorAdapter you are attaching to is setup correctly with the properties needed for updating:

SendUpdates = .T.
Tables = table to update
UpdatableFieldList = fields to potentially update
UpdateNameList = cross-reference of cursor fields to table.fieldnames
KeyFieldList = key field(s)

Without those being set up correctly, you won't get an update to the backend.