If you get error like "Extension with identifiers com.razer.common.razerhid not approved to load. Please approve using System Preferences." after avaddon's solution, try execute the following: sudo kmutil load -z -p /Library/Extensions/RazerHid.kext This command requires reboot to take effect. Finally, I was able to recognize DeathAdder Chroma from Synapse 2 on Big Sur. (USB un-plug and plug may be required.) Many thanks to avaddon - https://developer.apple.com/forums/profile/avaddon