Last night, I started getting an error in iTunes for Mac every time I tried to sign in to browse the Store or download app updates – “The iTunes Store is temporarily unavailable”. I looked everywhere and tried every trick in my arsenal, including an obvious restart of my Mac and even Keychain First Aid. I eventually found an Apple support document but that didn’t help either.
This morning I came across this discussion on Apple Support Communities and followed the instructions provided by Jerome Colas on September 30, 2013. I don’t know if this is a new problem with Mavericks or Safari 7, but it worked for me, so check it out if you’ve been having the same issue lately.