Many Thanks to @avaddon for his perfect answer , you have fix my issue . So for anyone updating to Big Sur and using a Razer Synapse 2.0 v1.88.20. After 4 hrs I've got it working. After update to Big Sur Synapse was loading for me but was not detecting devices. manually running  Code Block language sudo kextload /Library/Extensions/RazerHid.kext will error suggesting to Approve extension via System Preferences.  3rd Party extension popup and Allow never showed up in a pane. After digging around and looking up Razer TEAMID R2H967U7J8 I was able to manually adjust security settings: Boot into Recovery Mode Click the Utilities menu and select Terminal. Execute the following command: Code Block language /usr/sbin/spctl kext-consent add R2H967U7J8 • Verify that team got added Code Block language /usr/sbin/spctl kext-consent list Should output something like:  Allowed Team Identifiers: R2H967U7J8 Close the Terminal app and restart After this I was able to execute  Code Block language sudo kextload /Library/Extensions/RazerHid.kext Got popup and Allow button in System Preferences.  Allowed extension and restarted.  Got my Naga Epic Chroma back in Synapse after reconnecting it.