Error Opening Sound Devise

I got 95% of the way through a project, due the next day, “Error opening sound device”…come to a screeching halt.
As a donator to this application, and trying all setting changes, after many reboots and setting changes, I am perplexed.
OS X El Capitan
iMac (24-inch, Mid 2007)
2.4 GHz Intel Core 2 Duo
6 GB 667 MHz DDR2 SDRAM
ATI Radeon HD 2600 Pro 256 MB

Using Fosucrite/Scarlett 2i/4

See this FAQ page in the Audacity Manual: https://manual.audacityteam.org/man/error_opening_sound_device.html

WC