I need to reinstall High Sierra on a Mid-2011 MacBook Air that can't go any higher. I have a copy of the installer on my iMac but when I tried to use it, I was told it was corrupted. So I went to the Mac App Store as directed by Apple clicked on Purchased, and searched for it but was told nothing found. I want to put the installer on an USB drive, boot the MBA from it and install High Sierra.
MacBook Air 11″, macOS 10.13
Trash the downloaded Install macOS High Sierra app. It can't be used.
Rather than attempt to determine the reason for the misleading "corrupted" dialog, I suggest creating a brand new, temporary User Account on that Mac: Set up users, guests, and groups on Mac - Apple Support. Be sure to give it Admin privileges.
Log into that Account, and download the installer app from the App Store as described in How to download and install macOS - Apple Support. When it finishes downloading, create the "bootable USB installer" according to Create a bootable installer - Apple Support.
I just did all of that on an eligible Mac and can confirm that it still works.
The Recovery method of installing High Sierra is no longer an option for us. Apple removed that ability several months ago. I have been expecting them to pull it from the App Store as well. At least as of a couple hours ago that has not happened.
When you're all finished you can delete the temporary User Account: Delete a user or group on Mac - Apple Support.
Trash the downloaded Install macOS High Sierra app. It can't be used.
Rather than attempt to determine the reason for the misleading "corrupted" dialog, I suggest creating a brand new, temporary User Account on that Mac: Set up users, guests, and groups on Mac - Apple Support. Be sure to give it Admin privileges.
Log into that Account, and download the installer app from the App Store as described in How to download and install macOS - Apple Support. When it finishes downloading, create the "bootable USB installer" according to Create a bootable installer - Apple Support.
I just did all of that on an eligible Mac and can confirm that it still works.
The Recovery method of installing High Sierra is no longer an option for us. Apple removed that ability several months ago. I have been expecting them to pull it from the App Store as well. At least as of a couple hours ago that has not happened.
When you're all finished you can delete the temporary User Account: Delete a user or group on Mac - Apple Support.
You’ll find the App Store download link here: How to download and install macOS - Apple Support.
Might try this old cure...
If you get a corrupted message...
Naw, it's not damaged, it's just that you have an old copy already in Applications, there are 2 cures...
If you’re short of bandwidth or data… Disconnect from the Internet & set the Date back to 2014, then you can run the Install MacsOS ******* App in Applications, so expired Certificates are not expired.
Or...
Trash the Install MacsOS *******.app in Applications then restart, a new copy more recent version can be downloaded... maybe.
If you only need to reinstall macOS : How to reinstall macOS - Apple Support. There is no need to download the installer.
Do you have a friend that can make a USB stick for you?
Does holding Option key at startup show Boot choices?
I tried that on my iMac but it didn't work probably because the iMac is also maxed out at MacOS 10.13.6. I get this message:
Is there any other way?
The problem is the MacBook Air WON'T get to a log in screen I can't even get into safe mode. So I figured I would try reinstalling MacOS 10.13.6 High Sierra from an USB drive.
That is why I need to create a bootable flash drive with High Sierra installer so I can give the MBA a valid boot drive since it won't boot up from the internal SSD.
Where to download MacOS 10.13.6 High Sierra?
