Can't Install Mac OS X 10.8 after erase

Question

I bought a used MacBook Air last year from another region here in Ghana. And the man re-installed Mac OS X 10.8 for me. And I typed my apple ID I have been using on my iPhone and everything has been moving smoothly until I mistakenly 'Erased' my entire 'Macintosh HD'. So I followed some instructions from Apple holding the 'Option' button and etc. But finally, after I type in my apple ID and password in Utilities, I get the error "This item is temporarily unavailable. Please try again later". I have tried again later with other WiFI networks and what not. But still.

Answer 1

Thank you. Your Mac shipped with Lion. Which means you can do an Internet Recovery startup by turning the Mac on and immediately holding down the Command+Option+R keys. This will boot the Mac to its firmware. When the work screen appears, you first need to make sure the drive is completely wiped clean, or it may try to install Mountain Lion, which is what the hidden Recovery partition should be. However, you will not be able to reinstall Mountain Lion since it will ask for the former owner's App Store ID and password.
So follow these steps:
1) Make sure you know your router's wireless password since you will be required to have an Internet connection to reinstall OS X. Better would be to use a wired Ethernet connection to your DSL or cable router.
2) When you boot to the Internet Recovery Screen, first choose Disk Utility. When the screen comes up, you will see something similar to this:
I have multiple hard drives here, you will likely only have one showing. But what you need to do is click on the physical drive name. That will allow you to partition the drive. Click on the Partition tab at the right to get this screen:
Where the drop down menu says "Current", change it to something else. Even if the drive is already one partition for the whole thing, and you only want one. In which case, choose "1 Partition". You'll notice that the Options button is now no longer grayed out. Click that and make sure the radio button for GUID Partition Table is selected. Click OK.
Make sure the Format is Mac OS Extended (Journaled). It should be by default. Make the Name anything you want to call it. Click Apply. It will take just 10 seconds or so to complete. When it's done, quit Disk Utility.
3) Now choose to install OS X. The machine specific version of Lion for your Mac will be installed.
4) When the install is complete, you can open the App Store and create your own account. Normally, you use the same Apple ID and password you use to access these forums.
5) Then it's up to you what you want for an OS. You can either stay with Lion, or upgrade. It's $20 to purchase Mountain Lion, 10.8.x. You'll receive an email with a redemption code you use in the App Store app to initiate the download and installation. Once you have it installed, that purchase will forever remain under your list of purchased items and can be reinstalled at any time. Or, you can jump all the way to Yosemite, 10.10.x for free. Mavericks, 10.9.x is not on option as Apple has pulled it from the App Store.