某天将MAC笔记本接到外接显示器上，狂点了几下鼠标，结果导致MAC死机。后来，多次外接显示器都是死机状态。查了很多中文帖子都无法得知原因，最后还是英文搜索搜到解决方法如下：

Open up Terminal

If you are using 10.6 and higher

sudo kextunload /System/Library/Extensions/InsomniaT.kext

sudo rm -rf /System/Library/Extensions/InsomniaT.kext

If you are using 10.5 and higher

sudo kextunload "/System/Library/Extensions/InsomniaT (10.5).kext"

sudo rm -rf "/System/Library/Extensions/InsomniaT (10.5).kext"

If you have the old app

sudo rm -rf /Application/Utilities/InsomniaT.app

To remove the preference pane and command line client and uninstaller

sudo rm -rf /Library/PreferencePanes/InsomniaTPref.prefPane

sudo rm -rf /usr/local/bin/insomniat
sudo rm -rf /usr/local/bin/uninstallInsomniaT.sh

Go to System Preferences, right click on InsomniaT and choose to remove the preference pane.

虽然我也不理解其中原因，但是执行sudo rm -rf /System/Library/Extensions/InsomniaT.kext后，确实解决了外接显示器崩溃的问题。