Today's game update includes some significant upgrades to the patcher for both the Windows and Mac versions of the game client. These upgrades should greatly reduce the number of crashes/freezes that occur during the launch of the game. Additionally, users are no longer required to manually delete game files after uninstalling the game to ensure that a fresh installation functions properly.
HOWEVER...
Any user that did not receive the latest game patch (ver. 1.13.44, released 10/10/2013) will receive an error when attempting to update the game client with today's patch. This issue can only be resolved by uninstalling the game and then using the latest installer at www.pokemontcg.com/download to put the game back onto their system.