Alert for MacOS 13 Ventura users only:

Any user attempting to use the drag and drop option to transfer a micro:bit .hex file using the Finder application on the newly released macOS 13 Ventura (release date 22 October 2022) or the early MacOS releases up to 13.1.x will see the following error appear:

“The operation cannot be completed because an unexpected error occurred (error code 100093)."

This issue affects both micro:bit V1 and micro:bit V2.


Apple applied a fix to their MacOS, with the release of version 13.2.x in January 2023.

If you are unable to update your MacOS, there are two workarounds for users.

Workaround 1: Use web USB

Programming the micro:bit with web USB still works as normal and is the recommended approach for users on all operating systems. Read about using web USB in the micro:bit guide.

If you have .hex files on your computer that you would like to program to the micro:bit you can drag and drop them into the relevant editor (MakeCode or Python) and use web USB to flash them. 

If your .hex files were not created with these two online editors, you can use a web USB flashing tool we have published.

Workaround 2: For users who cannot use web USB

Use the built-in application called Terminal.

The terminal app can be found via the Launchpad or Finder:

  • Click the Launchpad icon, click on the Utilities Folder, then click Terminal.
  • Or in the Finder, open the /Applications/Utilities folder, then double-click on Terminal.


If you would like more information about using Terminal and the command line, please read the Apple Support guide for use with Terminal on the Mac (Execute commands and run tools in Terminal on Mac – Apple Support (UK)


Basic use and rules of Terminal

The terminal application has many built-in commands, some of these may not be familiar to you and you should only need a single command (rsync) to achieve the goal of transferring the .hex file to the micro:bit. However, be aware that every character you type matters, especially spaces.


While it is normal to use the ‘cp’ command for this sort of operation, in macOS 13, this also does not work properly for programming the micro:bit, and can result in an error 504 on the micro:bit display.

Instead, we will use rsync

  • rsync – a powerful copy command to enable your .hex file to be transferred to the micro:bit

To run a command, just type it in at the cursor and hit return to execute the command.

Graphical user interface, text

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For example:

Type the following command replacing the name microbit-smile.hex with the name of your micro:bit .hex file.

rsync ~/Downloads/microbit-smile.hex /Volumes/MICROBIT/


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The orange LED on the back of your micro:bit should blink and after about 20 seconds, your program should run.

In macOS, you can also drag files from Finder or the desktop into the terminal window instead of typing their full path.