> I opened one instance of FoxPro 5.0 and issued OPEN DATABASE {name}
>
> I then issued the command USE {name}.DBC, and got the "File is in use"
> error.
>
> I then opened a second instance and issued USE {name}.DBC, followed by
> BROWSE, and everything worked.
>
If it let another instance open it, it means it's not open exclusively,
so you should try
sele 0
USE {name}.DBC again alias anything_else_just_not_the_same_name
Works for me, even while the .dbc is still open in the database designer
window.