= UPdate: After the problems below, i uninstalled the tascam driver and the OS disk became poop on a rope. I should have read more before wasting my time. Way too many messages everywhere about problems with these devices, including lots of sonar users who gave up.
(See details below if you have any interest whatsoever.) I am prolly not purchasing a tascam product again. A waste of time, and lost income after the OS disk refused to boot after uninstalling the driver. AND:::: the windows error sound was heard by all. (Did not update to 2.1) I tested with media player and videos: all good. I uninstalled the 16x08 driver, restarted, and installed the driver, restarted. Installed a Mailiya PCI-E to USB 3.0 2-Port PCI Express Card, with NEC chip. Today I installed a new USB card because a Tascam tech told another poster to do this and it fixed their problem with noise. I could still use the media player and play youtube vids, with sound just fine. Installed the latest sonar version and SAME results: immediate drop-out and error about device not found.
Meanwhile, back at the ranch: I installed the 16x08 on another AMD based computer. Sent message to them on Monday: NO response. Tascam us-16x08 UPDATE ABSOLUTELY NO JOY sonar: only audio dropouts now