Mac OS - Impact of hack to non-administrator account

[avz]

Note that if you use FileVault (i.e. disk encryption) then any user account has (by default) permission to unlock the drive. If the password is compromised or too easy to guess, then you are jeopardising your own data too.

What if you(before selling your FileVault enabled Mac) create a new admin account for a new owner then login in with it and delete your original account. Will your data be safe in this scenario?

 

[KALLT]

What if you(before selling your FileVault enabled Mac) create a new admin account for a new owner then login in with it and delete your original account. Will your data be safe in this scenario?

Any new account added (whether admin or not) will be able to unlock the drive and get access to all of its contents. You are basically handing them their own pair of keys. They will have access to all of its data then. You should always wipe the drive completely and reinstall macOS before you give away a Mac (and follow additional steps recommend here).