How can I install Mac OS X 10.7.5 on my Macbook Air? I have a 2008 Macbook Air that was running Mac OS X 10.7.5. I purchased it on eBay and wanted to do a full OS reset. This being my first Apple computer (and ONLY Apple computer in my household), I figured it would be a simple procedure -- 1. Wipe the partition, 2. install the OS. Boy was I wrong.

The only thing the computer boots into is "Mac OS X Utilities". When trying to reinstall Mac OS X, it comes up saying "This item is temporarily unavailable. Please try again later." Ok, I've tried "icloud.com" where it comes up telling me I don't have a supported version of Safari (lol). I tried the "recovery boot with internet" or whatever, and the 2008 model doesn't support that.

After some research, I've determined I need the operating system (the .app file), and from there, I can put it into TransMac to copy it onto a USB drive, then insert it in the computer. Simple enough, right? Nope! The file doesn't exist online and the only way to obtain it is through the Apple app store.. How can I get on an apple app store? I need a Mac, of course!

What can I do???
The MacBook Air should have come with either a DVD or a USB pen-drive containing the operating system installer. If you haven't got these in your eBay purchase, try contacting the seller to see if he'll send you a digital or physical copy. Otherwise you can try to borrow from a friend.

If you have a USB pen-drive with the installer, you can ofcourse install directly from there.

If you have a DVD with the OS X installer, you can use a USB-connected DVD-drive to run the installer. If you haven't got such a drive, you can use the DVD-drive on a seperate PC (or Mac). Apple has a guide for that scenario here:

https://support.apple.com/en-us/HT3263#

The easiest way to solve your problems seems to be to take the Mac to an Apple Store. They should be able to reload the OS on your MacBook Air. I don't know if the original USB pen-drives are still sold at Apple Store as they were back in the day.