I must be missing something:

All from the command window VFP6 - clean load of VFP.

? fopen('inv_mast.dbf',12) && returns 6 (file opens)
? fclose(6) && return .T. (file closed)
select 0
use inv_mast shared
? fopen('inv_mast.dbf',12) && returns -1 (unable to open file)
use in inv_mast
use inv_mast excl
? fopen('inv_mast.dbf',12) && returns -1 (unable to open file)
use in inv_mast

What gives? - I do have Hackers Guide - great reference - I have tried all the other fopen parameters - all return the same for me.

Thank you very much for your help.