I was scammed by fake customer who told me to sigh out of my Apple ID

Hi IvanOlytskyi,

I would recommend erasing the Mac and reinstalling macOS, which John Galt also suggested. If you run into an Activation Lock screen, Apple may be able to remove Activation Lock for you if you can provide proof of ownership.

You were correct to sign out of your Apple ID since you were planning to sell the Mac, but signing in with the customer's Apple ID was a mistake. Typically, a Mac sale should look something similar to this:

1. Sign out of your Apple ID and disable Find My Mac.
2. Erase the Mac, and reinstall macOS if needed.
3. When the Setup Assistant appears, press Command-Q to shut down the Mac and leave it in a factory state.
4. Collect and verify payment from the customer or buyer.
5. If applicable, ship the Mac.
6. When the customer receives the Mac, let them complete the Setup Assistant on their own.

Sidenote: Don't buy a used Mac unless you can verify that the seller completed the first 3 steps.

Erase the Mac: Erase all content and settings on Mac - Apple Support

You must never let anyone that you do not know or trust sign in to your Apple device using their Apple ID, but you know that by now.

IvanOlytskyi Said:

"I was scammed by fake customer who told me to sigh out of my Apple ID: Hi, I am Ivan from Ukraine. I am a firstly user of the Macbook Air. I was scammed by fake customer, who told me to sigh out of my Apple ID account and sigh in to his Apple ID account on my device.[...]"

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Troubleshooting a Compromised Account:

Do these things to secure your account.

A. Verify your Devices:

Verify that all device are logged in to your account, by using this link: Check your Apple ID Device List to See where you're Signed in - Apple Support

B. Modify your Credentials:

Having been stollen, someone lily has your credentials. So, by all means, modifying them.

• Modify: your login credentials (Using Both a New eMail and a New Password for each and all sites)
• Associate: a different method of payment to your account
• Enable: Two-Factor Authentication for Apple ID and for all other accounts that have such an applicable option