Update to above:
Oddly enough, download of fresh copy of TurboTax and re-install without de-install, then running as administrator allowed Netfile to process this one return.
Specific example: code 316 was not accepted during Netfile before the re-install, while official Saskatchewan code of 8574 [Purebred Horses, Breeding, Mares was not enterable before and accepted after, but programatically changed back on entry in the Netfile error diagnosis screen to code 316.
Note that this was only attempted on a hunch after 37 years (so far) in Systems, without significant expectation of success. Some attempts may require unspecified secret incantations.
Grumpy Old Farmer
