HT2589: Using an existing Apple ID with the iTunes Store, Mac App Store, and iBooks StoreLearn about Using an existing Apple ID with the iTunes Store, Mac App Store, and iBooks Store
Currently Being ModeratedOct 22, 2012 12:57 PM (in response to Just Asking...)
Try deleting App Store cookies ...
Quit the App Store if it's open.
Now open the Finder. From the Finder menu bar click Go > Go to Folder
Type or copy/paste: ~/Library/Cookies
Click Go then move the com.apple.appstore.plist file from the Cookies folder to the Trash.
Launch the App Store. From the menu bar click Store > Sign In
Currently Being ModeratedOct 22, 2012 5:09 PM (in response to Carolyn Samit)
Thank you for your tips. I'm still getting the same issue. I have a similar problem with trying to login with the iCloud. I went to iCloud.com and logged in just fine, but I can't with my Mac.