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EV3 firmware update fails on macOS with NotAllowedError: Failed to open the device #2817
Description
Describe the bug
When I try to update my LEGO MINDSTORMS EV3 using Pybricks Code on macOS, the update fails because Pybricks cannot open the EV3 device.
The error shown is:
An unexpected error occurred.
Failed to open the device.
NotAllowedError: Failed to open the device.
I am trying to update because my current Pybricks installation on the EV3 appears to be an older version.
To reproduce
Steps to reproduce the behavior:
- Connect a LEGO MINDSTORMS EV3 to a Mac using USB.
- Open Pybricks Code in Google Chrome.
- Select/connect to the EV3.
- Attempt to update the device/firmware.
- Select the EV3 when prompted by the browser.
- The update fails and displays `NotAllowedError: Failed to open the device.
Expected behavior
I expected Pybricks Code to successfully open the EV3 over USB and proceed with the device/firmware update.
Instead, the EV3 cannot be opened and the update stops.
The error dialog says:
An unexpected error occurred. Please consider reporting this so we can make a better error message. Click the Copy Error Message button below to copy the technical details and paste it in the bug report. Also include the operating system you are using, the web browser you are using and the actions you performed that led to this error.
Failed to open the device.
NotAllowedError: Failed to open the device.
Additional information
Device: LEGO MINDSTORMS EV3
Operating System: macOS 15.6
Browser: Google Chrome
Connection: USB with USB-C adapter
Error: NotAllowedError: Failed to open the device
Activity
dlech commentedon Sep 4, 2026
I just successfully flashed the firmware on my M1 macbook, so it should be possible.
When you first plug the EV3 into the computer when it is in update mode, you should see something like this.
I'm guessing the error is because you didn't click Allow there.
Hope that helps.
laurensvalk commentedon Oct 12, 2026
This might be something we need to add to the instructions.
@dlech: Do you get that notification once, or do you get it again later if you accidentally dismiss it?