Delete the app and then try to install it again. Before deleting any apps from your Mac you should make sure you have a recent backup of all your valuable data. It could be that the app, or the app installer, has become corrupt and this is why your Mac won’t install or update it.
- How To Install App On Mac From Unidentified Developer
- How To Allow App Installation On Mac
- Run Mac Apps On Windows
Disconnecting from the Internet wouldn't have helped in the least since the OS had already finished downloading and was installing Mavericks from the hard drive.
How To Install App On Mac From Unidentified Developer
You had OS X, 10.7 Lion on the drive, not iOS anything. OS X is the operating system for Mac computers such as the Mac Pro, iMac, Mac Mini and MacBook Pro. iOS is a completely separate OS and is only for mobile devices such as the iPhone and iPad.
Since Mavericks is now on the drive, the only way to go back to Lion, which your Mac came with, is to do an Internet Recovery. You WILL lose everything on the drive. Make sure to back up files you cannot afford to lose, first.
How To Allow App Installation On Mac
Run Mac Apps On Windows
Restart and hold down the Command+Option+R keys. Launch Disk Utility and erase the drive. Then install OS X. The version of Lion that came with your Mac will download from Apple's servers and install.