I've searched all over for a solution. Whenever I try to download a new app from the Mac App Store, it swooshes over to Launchpad and stays there forever in 'Waiting' mode. If I were to reboot or log out/in, that new waiting app disappears from Launchpad and I will have to try and redownload again but only to receive the same response. (It's funny, it doesn't even appear on my new apps purchased list in iTunes). If I try to update an app using the purchases or updates tab on the Mac App Store, the update button will briefly disappear upon click only to reappear a few seconds later without any response in either the App Store or the Launchpad. I have several apps that I have purchased that need updating and I cannot do so. I've tried several solutions previously suggested - force quitting, clearing the Library App Store cache, signing out and in of the App Store, updating my credit card info, switching from ethernet to wifi, deleting apps, etc. I just can't seem to get the App Store to download or update. Any suggestions?