Error downloading Mountain Lion from AppStore I had an error while downloading OS X Mountain lion from the App Store.

It tells me this message "An error has occurred" and nerver wants to start downloading again.

What should I do now!!!
Muhammad Reda - I've got the exact same issue with my iMac. I contacted the Apple Store and they said because so many people are trying to download it, the download button should come back on at least some time in the next few days. Hope this helped.