我晚上重启了的,刚刚第一次使用unload。 还是这个提示喽。 哈哈哈
bash-3.2# kextunload /System/Library/Extensions/AppleHDA.kext/
(kernel) Can't unload kext com.apple.driver.AppleHDA; classes have instances:
(kernel) Kext com.apple.driver.AppleHDA class AppleHDAStream has 2 instances.
Failed to unload com.apple.driver.AppleHDA - (libkern/kext) kext is in use or retained (cannot unload).