Hi !
Sorry to read that. Let's try to resolve this:
First, unplug your BeatStep Pro from your computer.
1. Please remove any HUB from your setup.
2. Delete the BeatStep Pro + BeatStep Pro Updater from the Audio MIDI Setup.
(Applications > Utilities > Audio MIDI Setup > Window > Show Audio Devices)
3. Plug your BeatStep Pro and try to proceed the firmware update.
/!\ During the firmware update, instead of turning the BeatStep Pro OFF / ON, please unplug and replug the BeatStep Pro USB instead /!\
Keep me informed if it fixes your issue.
If the issue persists, the best would be to contact our support team:
https://www.arturia.com/support/askforhelp/issuesBest Regards.
Edouard