PS: I just came across this article - they claim you need at least 8. There was a recent thread a bit similar to this one that might give you a bit more insight on upgrades to El CapitanĮl Capitan on Early 2009 MBP and other stuff The Apple file system is the most significant feature it brought. There are few bells and whistles, but the changes are noticeable and positive. High Sierra emphasizes the already-existing benefits of MacOS previous system, Sierra. The ElCapitan installer is just over 6 GB and it will fit on a 8 GB USB flash drive, but it may require more than 8 GB during the installation process - it would be good if you could free up a total of at least 12GB on your hard drive. In essence, High Sierra took what was good with Sierra and developed it into a more comprehensive software. The other is that the amount of hard space at 8.8 GB I think is marginal. Also note that make and system headers are not included in this package so you will also need to install XCode3 (10.6), which is available for free with a. You should be able to verify that the installer you have is not corrupt. One is that your El Capitan macOS may be corrupt because of the very long download - I think you mentioned 14 hours which probably means dial-up. Click to expand.Also not true - El Capitan is available from Apple for any Mac where El Capitan is the latest macOS that Mac supports - and your iMac is one of those
