I'm on a MacBook Pro, mid 2009, OS X 10.10.
An update to Yosemite (10.10.2) came out five days ago, but going to the Updates tab in App Store only returns a dialog box with the following message:
An error has occurred
Can't connect to the Apple Software Update server.
I have turned off Firewall, logged out/in from App Store, removed App Store cookies - but despite this and after googling over an hour I'm still clueless.
Any ideas what could be the problem?