macOS could not be installed on your computer

Do you have a MacBook that supports Sierra?

You will need one of the following devices to install Sierra:

• iMac (Late 2009 or newer)
• MacBook (Late 2009 or newer)
• MacBook Pro (Mid 2010 or newer)
• MacBook Air (Late 2010 or newer)
• Mac mini (Mid 2010 or newer)
• Mac Pro (Mid 2010 or newer)

If you have one of the devices mentioned above:

You will have to clean install macOS Sierra and then retrieve your apps and data from a Time Machine back-up.

Before performing a clean install of macOS Sierra, be sure to have backed up your data on a Time Machine (Use Time Machine to back up or restore your Mac - Apple Support).

Performing a clean install of macOS Sierra requires some technical actions, you can read the following article to successfully do this: https://www.macrumors.com/how-to/macos-sierra-clean-install/

If you just reformat your drive during the installation, you will wipe all the data on it. Then your installation won't reproduce the error you received 🙂

Edit: In the article they use the Terminal to create a bootable drive. There's an app for that (https://macdaddy.io/install-disk-creator/)

1. Download Sierra from the App Store --> https://itunes.apple.com/nl/app/macos-sierra/id1127487414?mt=12

2. Use the Disk Creator to select 'Sierra' and put it on the USB-drive (The USB-drive will be formatted).

3. Disk Creator is actually quite self-explanatory.

Hope my information was of value, if you have any further questions, please tell us.

Are you able to provide us any screenshots from your screen with the error saying that the First Aid process failed?

You can make a screenshot with Cmd + 3, or if you want a part of your screen screenshotted you can use Cmd + 4. The screenshots are saved to your Desktop.

I'm sorry to say this, but this way you are not being informative at all.

Could you send me the details of the error message? On the pop-up message you see 'details'. Please click on that and share me whatever is in there. Please type the details because your photos are extremely blurry and hard to read.

Launch Disk utility, choose the affected volume and click Repair Disk. Let us know what it reports.

You just have to make sure that your drive that you're installing macOS onto is completely formatted and empty.