I have a table which contains all my software instances. I have a sub form which allows me to add instances for hosts. Just recently (I think) when I add an instance, even though I can see it in the Instance table, Access 2010 does not find it and return it to me afterwards.
On checking the relationships (one to many) I now see table names with an appended '_1'.
OH MY GOD .... so .. in the relationships tab, it is possible that the screen has scrolled right down, meaning you can't see the original tables up at the top. Adding more tables, then refreshes them into the same window as _1 to avoid dupes.