For some reason I have started having trouble getting serial output from Serial.printf() statements in programs with a Teensy 3.x target.  I created a minimal program to illustrate the problem 

/*
    Name:       Printf_Demo.ino
    Created:	5/24/2020 10:13:54 AM
    Author:     FRANKNEWXPS15\Frank
*/


void setup()
{

    Serial.begin(115200);


    // wait until serial port opens for native USB devices
    while (!Serial)
    {
        delay(10);
    }

    Serial.print("Serial.print without a terminating linefeed");

    Serial.printf("Serial.printf without a terminating linefeed");

    //Serial.println("Serial.println");
}

void loop()
{


} 

When this program is compiled in VS2019/VM with a Teensy 3.2 target, with all other settings unchanged, no serial output appears in the serial monitor window.  However, if I uncomment the "Serial.println()" line, then all three strings appear, all on one line, as expected.

This same program, when compiled in the Arduino IDE works fine; when the last line is commented out, I get the first two strings on one line, and with it uncommented, I get the same behavior as in VS/VM - all three strings on the same line.

I must be doing something wrong, but I have no idea what that might be.  Any help would be appreciated.  I have attached a ZIP file containing the verbose compiler output, and my entire project folder.  If anything else is required, I'll be happy to provide it

TIA,

Frank

Sorry - forgot about the build properties. Here it is again.

Frank
'

Thanks for addressing this so quickly -- and for letting me know that I'm not entirely crazy 

Frank