Used mac previous owner info still on after reset

[TurboJobo]

I bought a used macbook pro m1 14.2" from offer up and the first thing i did was to boot up in disk utility and wipe the hard drive. Reinstall the OS and log in into my icloud. All good and regular up into i open safari and went into facebook. The old owners email and password were saved by safari along some other websites. why? the macbook was only 2 weeks old and didn't have anything on the hard drive. Are my passwords and email compromise too since ive sold other old macs before doing the same thing when you boot up to erease the disk and reinstall the os.
The macbook was 1100 dlls and that's why I got it. it perfect no damage at all

 

[chabig]

Perhaps you wiped the System Volume but not the data volume. If it was running Monterey you wasted your time (sorry to tell you that). All you need to do is open System Preferences, and then select from the menu bar, System Preferences > Erase All Content and Settings... That will erase everything from the previous user. Then set up the machine from scratch again.

 

[haralds]

Also. disk ownership might still retain the original owner's identity. Did they wipe the system and disconnect it from iCloud?
The only way to completely clear the disk is to clear the whole Volume Group and start a fresh install from recovery or do a System Restore from another Mac using Configurator 2. But if the ownership was not cleared, you will not be able to initialize the system when it "phones home" unless you know the original AppleID and password.

 

[TurboJobo]

well what i used to before it was turn on the mac and then keep holding the power button until i got into the menus and deleted the hard drive info from disk utilities and then reinstall the os.
the previous owner did not even log in into his icloud.

 

[chabig]

My guess is still that you didn't do it 100% correctly. I suspect you deleted and reinstalled the operating system without deleting user data. With later operating systems, it's not as simple as it used to be, because user data is on a volume separate from the operating system. Pervious user data left on the machine is evidence that you didn't do it right. Now, you should probably start over by carefully following these instructions from Apple to delete all user data.

Use Disk Utility to erase a Mac with Apple silicon - Apple Support

How to erase (format) the built-in startup disk of a Mac with Apple silicon.

support.apple.com

 

[TurboJobo]

My guess is still that you didn't do it 100% correctly. I suspect you deleted and reinstalled the operating system without deleting user data. With later operating systems, it's not as simple as it used to be, because user data is on a volume separate from the operating system. Pervious user data left on the machine is evidence that you didn't do it right. Now, you should probably start over by carefully following these instructions from Apple to delete all user data.

Use Disk Utility to erase a Mac with Apple silicon - Apple Support

How to erase (format) the built-in startup disk of a Mac with Apple silicon.

support.apple.com

thats the method i was using when restoring the macs. after disk untily deleted everything i went into reinstall the macos