Hi MasashiKurita and Quinn, I have the same basic goal and the same basic issue -- I want to install a kext on my own machine for research purposes, but I cannot get it to install on macOS 12.5.1. (The kext installs and runs perfectly on 10.15.7.). Yes, I have disabled SIP, yes I have signed it as "Sign to run locally," yes I have changed the ownership "root:wheel" and moved the bundle to /Library/Extensions, yes I have granted permission in the "Security & Privacy" panel, and yes I have restarted. "sudo kmutil print-diagnostics [kext file]" tells me that the dependencies are OK and does not complain about ownership. But it also tells me that the kext has a "Bad Code Signature." The "System Information" utility similarly reports a "Kext signature validation error code -67050." What is the trick? Apple Developer told me that I could install a kext on my own machine without a "KEXT-enabled Developer ID." But how -- what is the magic combination? MasashiKurita, you wrote that you "successfully loaded [your] first kernel extension" on macOS 12.5. How did you do it? Thanks for your help. Eric Grant