@D. Tempest, it seems you spent considerable time crafting your reply. However,
@ilstefano only made a general reference to "the latest drivers for TASCAM and Windows".
The OP didn't tell us which version of the firmware is running on the Model 16, which version of Windows is on the computer, and which specific TASCAM and Windows drivers were installed.
Seems to me having that formation from the OP beforehand would be critical to solving the OP's specific issue; and for the OP to benefit from the solution that worked for you, your operating setup would need to be very similar to the OP's, yes?
IMO it's hard to say if such detailed steps would work for the OP if the OP's firmware, OS version, and installed drivers are at this point unknown. Have you confirmed that the troubleshooting steps you've developed are generic enough to apply to all Model16/Windows OS/Driver combinations? Otherwise the OP may become even more confused and waste time going down rabbit holes that don't apply to his/her operating setup.
Be that as it may, what are your "steps 1 and 2" left unmentioned? Why not include your ommitted information, instead of starting with a self-numbered step "3" that might confuse some finding this thread in the future who may be unfamiliar with obtaining and installing the correct TASCAM and Windows drivers?