Jim, I am sending this video so you can hear the strange sound. The fist few seconds are Winlink and then I switched to VarAC. Note the "Busy" in the upper left corner

Please don't take this the wrong way, but I am an experienced Winlink and FLDigi user. Yes I am using the HF profile, not the FM, and the program opens VARA (not VARA FM). The radio is in USB-D mode and I am using "CAT" control at 19200 for both PTT and Frequency Control. The setup is identical to the one I use for my IC-7300 except for the radio model. BTW, I have tried other baud rates as well with no change.

Additional info. The radio works fine with FLDigi and Winlink on HF. If I try VarAC enough times the noise stays in the radio on all HF bands and I need to do a hard reset and re-program in order to get rid of it. Also, I have tried 2 other computers with the same results.