App Store won't let me log in

hi i had the same problem what you have to do is go on the app store and at the top click store, and then purchases and then it should say os x mountain lion and all the apps you have downloaded, next to it if you hover the mouse over os x mountain lion theres and x button to the right click it and then re download it and should work fine worked for me

because the app store won't let me log in.

The App Store was down for about 15 minutes, but you should be able to login now.

It's not a certificate issue.

I'm having the same problem. It's not a wrong password issue, because when you enter the wrong password, it tell you. The issue I'm having is that the login window goes away, like it has accepted the password, and then immediately presents me with the login window again. I even tried chaning my password, but I'm still getting the same issue with the new password. I upgraded to Mountain Lion on Friday. I'm wondering if this is a bug in the OS.

Guess it's a bug in MacOS 10.7.4 - and I said before: We need a fix

Same here. Also can't log in.

Also cannot log into App store. Can someone reply?

I have a similar issue. My IPad has been automatically logged in to the store since I got it so it greets me with my name and such, but when I tried recently to redeem a gift certificate I got from my mother I get a window that says "sign in required press continue to sign in and then redeem.". I sign in with my password and then it seems to be doing something, but rather than redeeming the certificate, I get another window saying the same thing. I know it isn't a failed password because I was able to log into both game center and this support website. I don't know if this outcome is from the same cause as the one fore mentioned, but it seems similar and I am equally frustrated.

I have a similar problem. I tried to download mountain lion last night, and the internet was extremely slow. i woke this morning and found out that the download failed, and i dont know why. i tried to download again, but i couldn't log in with my APPLE ID, which was exactly the same with your issue. i can't view my purchases, it's so frustrating. when can this be fixed!!!??

I'm having the same problem.... I open app store, then go to the menu bar and click store then click sign in and nothing happens. It's like I diden't even click it. I am very unhappy. We need a fix.

Same exact problem here. At first I was logged in but wasn't able to update/download anything. Now when I select Sign In, absolutely nothing happens.

I Have the same problem and ive only had it a day what can i do as i know my password and username it just says wen i try to log in "This Apple ID Has Not Yet Been Used In The Itunes Store ? is there anything i can do ?

I have exactly the same problem...but I am TRYING to upgrade to Mountain Lion...everything is fine on my iPad with the same account, but I get exactly the same as you..I'm stumped...thought Appled was supposed to the anti-PC, but it's just as buggy!! Is there any solution to this?

I can't sign on to the app store nor icloud. My ipad and iphone work just fine. I can't upgrade apps and I can't access my email.