Hi, hope you can help, I've tried to install High Siera on my iMac 12.5 2011, delete all history and signed out, upon running download a drop down box said Download Required !!!! Anyone had this ?? It won't go past this to download, I'm at a loss, I contacted Apple Support and was told the iMac is obsolete?? It was fine yesterday was my reply, they wasn't very helpful, thanks for any help, RM