I have table buffering set to 5 but when I issue TableUpdate(.T.,.T.,MyTable) it returns true, but the table is not really updated. The values in the fields are not changed. They are changed on the screen by editing, and the tableupdate returns .T., but the physical table is not changed.

Shouldn't that be an Integer as the first parameter in tableupdate()? Such as TableUpdate(1,.t.,MyTable)?