Prior to following this guide from user: Avaddon - https://developer.apple.com/forums/thread/649829?answerId=646433022#646433022 I had similar issues to most people. After updating the OS Synapse 2.0 was unable to recognise the device. I followed Avaddon's guide and to my surprise the software detected the mouse. However, I was unable to assign buttons using the keyboard function. No buttons I pressed were recognised and the 'ok' button was greyed out. The basic functions were still working, of course. But you don't spend hundreds of pounds on a mouse, which has more than 12 buttons, to use it for its 'basic' functions. I'm wondering if the keyboard security function, brought about by the Big Sur update, is preventing this and question if there is another command which would help bypass/allow its free use. I hope I made sense! Sorry and thank you :( Product: Razer Naga Trinity