you wrote "A Share through the network means it is owned by that computer where it is located. NAS bypasses ownership. It is Network Attached, meaning a direct access is possible. Not Shared, but Common. Nothing is managing that it is "checked out" more than once."

I get how that works, but I see that as a flaw in Lacerte. Other programs identify files in use even when accessed via  a NAS. Open an Excel file hosted on a NAS drive that is already open by another user and it will tell you that the file is already open and can only be opened read only.

Anyway, thank you for the explanation.