Reinstall OS X El Capitan
I have a MacBook Air 2011 running OS X El Capitan. I reset it yesterday, but I'm unable to reinstall its OS. It's showing "A required download is missing."
Please help.
Question marked as
Try booting into Internet Recovery Mode using Command + Option + R to see if you can access the online macOS 10.13 High Sierra online installer assuming macOS 10.12.6+ has previously been installed sometime in the past. You may encounter a "server not found" error, so you may need to use Fix #3 in the following article:
If you actually want macOS 10.11 El Capitan, then after installing High Sierra you can download & create a bootable El Capitan USB installer to perform another clean install for El Capitan.
Create a bootable installer for macOS - Apple Support
If you have access to another working Mac model 2008-2015, then you may be able to use it to create a bootable macOS 10.11 El Capitan USB installer. That other Mac must also be compatible with El Capitan although it can currently be running any version of macOS. You can use the following article to confirm compatibility:
https://eshop.macsales.com/guides/Mac_OS_X_Compatibility