You could perform a safe boot & restart, which will clear out the boot caches sometimes. This will take longer to startup than usual and at the login window it will say Safe Boot in red letters. Just restart from the login window instead of logging in. The other thing to do would be to startup with disc 1 in the drive and run a verify disk permissions scan by bringing up Disk Utility from the Utilities menu at the top of the screen after selecting your main language. Security updates and OS updates modify the Receipts folder in the system Library and if it didn't quite complete or was interrupted somehow, the disk permissions scan is the only way to find out if something needs to be repaired on the software end.