Problem from lion 10.7.5 to mavericks

John I have the same issue, I cannot install. It just hangs it has been like this for more than 3 hours

I worked out a solution for myself, on a mid2012 macbookpro 13" running 10.8.5

I couldn't download Mavericks or any apps for that matter. Clicking on the Install App would show "Installing" for a few secons before changing back to the original button whereas the button should say "Downloading" if it is working. Also, you should be able to see the download progress in Launchpad, which I could not, there was no icon for Maverick.

My solution was;

Go to App Store > Store > Sign Out

Quit App Store

in the finder go to the menu Go (you must hold down the option key to see Library) > Library

delete these 2 files;

Library/Cookies/com.apple.appstore.plist

Library/Preferences/com.apple.appstore.plist

Restart your Mac. Go to App Store. Sign in. Downloading Apps should work now. Hopefully. I can see the progress in Launcher now. Is working for me so far but does not bode well for a new OS instal so far.

I tried 4 or 5 times to get the download to do more than sit there. Finally I took the iMac to where my router is (I had been going through wireless) and plugged it directly into the ethernet port ... and so far it is downloading fine. The iMac has a problem in general with wireless I find ... even with Netflix it will often stall and require a reset. I do not have that problem with the iPad or my Windows 8 box. I think this download issue is related to that ... reporting that there is no internet connection when indeed there is ...