Sometimes after updating LW, it's wise to remove the old LW firewall listing & re-add it to the OSX firewall 'if' you keep the OSX firewall turned on.

Check software update to be sure you have all OSX updates.

Also, try a safe boot & repair permissions. To do this, reboot the computer whilst holding down the SHIFT key. Can let go of shift key as soon as you see the mac osx icon appear. Safe boots take much longer to boot than normal.
Then open Disk Utility from the Utilities folder, select the OSX drive on left side of Disk Utility, press the Repair Permissions at bottom left of Disk Utility. Repair Permissions should be done after any OSX update.

Then reboot normally.