No device found when uploading sketch

using web IDE with MKRZero. trying to upload the blink sketch, this error keeps helping

arduino-builder/arduino-builder -compile -core-api-version 10611 -build-path /tmp/305096025 -hardware arduino-builder/hardware -hardware arduino-builder/packages/cores -tools arduino-builder/tools -tools arduino-builder/packages/tools -built-in-libraries arduino-builder/latest -libraries /tmp/049827170/pinned -libraries /tmp/049827170/custom -fqbn arduino:samd:mkrzero -verbose=true /tmp/049827170/Blink

Using board 'mkrzero' from platform in folder: /home/admin/builder/arduino-builder/packages/cores/arduino/samd

Using core 'arduino' from platform in folder: /home/admin/builder/arduino-builder/packages/cores/arduino/samd

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421] -> [/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]

Wait for the port to reappear

[/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421] -> [/dev/cu.Bluetooth-Incoming-Port /dev/cu.usbmodem1421 /dev/tty.Bluetooth-Incoming-Port /dev/tty.usbmodem1421]


Flashing with command:/Users/descobar/.arduino-create/arduino/bossac/1.7.0/bossac -i -d --port=. -U true -i -e -w -v /var/folders/l0/9k5wn5c55dx_fby9sl34556m0000gn/T/arduino-create-agent524804209/Blink.bin -R

Executing command: exit status 1

Hi there.

Going to suggest you read this first then add any additional information that you can.

Please take a few moments to Learn and Use the Forum.

Hello, Welcome to the Arduino Forum. This guide explains how to get the best out of this forum. Please read and follow the instructions below. Being new here you might think this is having rules for the sake of rules, but that is not the case. If you don’t follow the guidelines all that happens is there is a long exchange of posts while we try to get you to tell us what we need in order to help you, which is frustrating for you and frustrating for us. The people who try to help with your project.

It will help you get the very best out of the forum in the future.

  • Mention if you are using AI generated code it is important information.
  • Your OS and version can be valuable information, please include it along with extra security you are using. Antivirus etc.
  • Always list the version of the IDE you are using and the board version if applicable.
  • Use quote or CODE tags to add error messages as an attachment NOT a picture.
  • How to insert an image into your post. ( Thanks sterretje )
  • Add your sketch where applicable but please use CODE TAGS
  • Add a SCHEMATIC were needed even if it is hand drawn.
  • Add working links to any specific hardware as needed (NOT links to similar items)
  • Duplicate accounts are NOT allowed and any extra may be deleted.
  • Remember that the people trying to help cannot see your problem so give as much information as you can.


  • Ensure you have FULLY inserted the USB cables.
  • Check you have a COMMON GROUND where required. ( Thanks Perry)
  • Where possible use USB 2.0 ports or a USB 2.0 POWERED HUB to rule out USB 3.0 issues.
  • Try other computers where possible.
  • Try other USB leads where possible.
  • You may not have the correct driver installed. CH340/341 or CP2102 or FT232 VCP Drivers - FTDI
  • There may be a problem with the board check or remove your wiring first.
  • Remove any items connected to pins 0 and 1.


  • Close any other serial programs before opening the IDE.
  • Ensure you turn off any additional security / antivirus just to test.
  • There may be a problem with the PC try RESTARTING it.
  • You may be selecting the wrong COM port.
  • Avoid cloud/network based installations where possible OR ensure your Network/Cloud software is RUNNING.
  • Clear your browsers CACHE.
  • Close the IDE before using any other serial programs.
  • Preferably install IDE’s as ADMINISTRATOR or your OS equivalent


  • CH340/341 based clones do not report useful information to the “get board info” button.
  • NANO (Old Types) some require you to use the OLD BOOTLOADER option.
  • NANO (ALL Types) See the specific sections lower in the forum.
  • NANO (NEW Types) Install your board CORE’s.
  • Unless using EXTERNAL PROGRAMMERS please leave the IDE selection at default “AVRISP mkII”.
  • Boards using a MICRO USB connector need a cable that is both DATA and CHARGE. Many are CHARGE ONLY.

CREATE editor install locations.

  • On macOs ~/Applications/ArduinoCreateAgent-1.1/
  • On Linux ~/ArduinoCreateAgent-1.1/config.ini
  • On Windows C:\Users[your user]\AppData\Roaming\ArduinoCreateAgent-1.1

Performing the above actions may help resolve your problem without further help.

Language problem ?

Try a language closer to your native language:

Thanks to all those who helped and added to this list.

The error message is a good start but too many missing pieces of information right now.

Overall please let us know what Browser and OS you are using so we can try to reproduce. I just tried on Mac OSX Sierra and Chrome and it is fine.

Do you have the desktop IDE or other software that might be using that port? Do you have the Serial Monitor open?