Hi sghice,
Yep, I tried that but it has no effect. When the IDE gets to upload it shows the following:
Sketch uses 40644 bytes (15%) of program storage space. Maximum is 262144 bytes.
Forcing reset using 1200bps open/close on port COM3
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
Uploading using selected port: COM3
C:\Users\...\AppData\Local\Arduino15\packages\Seeeduino\tools\bossac\1.7.0-arduino3/bossac.exe -i -d --port=COM3 -U true -i -e -w -v C:\Users\...\AppData\Local\Temp\arduino_build_443199/DFPlayer_Test.ino.bin -R
Followed by a long delay and then it fails. I can upload the same code with the same versions of the IDE and libraries on the same version of Windows 10 on my laptop. It uses the same version/date MS driver and works reliably. So the only difference left is that the USB port different hardware. Whether that’s a V2 vs V3 difference or just that Intel ICH10 USB hardware on my desktop is too old I don’t know. Once the code is uploaded, I can re-attach the XIAO to the desktop and the Serial Monitor works perfectly so the Serial via USB is working.
It appears, on my laptop, to mount the XIAO as a USB drive and copy the code that way so it must be a peculiarity of that approach. All the real USB drives I have work fine on both machines.