Try this and also make sure your startup drive is properly selected in system preferences
Step 1 : Clear the dynamic loader shared cache
So First: boot in safe mode by restarting your mac by holding the SHIFT key immediately after hearing the boot chime. When you reach the login window, don’t even log in, just hit restart.
Step 2 : Rebuild Kernel Extension Caches
Open a terminal window and type the following commands:
sudo chown root:admin /
(the system will ask your password to grant access to the sudo chown command as this requires admin privileges)
sudo kextcache -system-prelinked-kernel
sudo kextcache -system-caches