How to access or delete an old mac.com account

Your old @mac.com address is tied to an Apple Account (Apple ID). Even if you didn't manually transition it to iCloud before 2012, the account itself still exists in Apple's system as an Apple ID login or alias (interchangeable with @icloud.com). 

If you want to permanently delete the Apple Account associated with the old @mac.com address:

1. Back Up Data: Save any remaining files, photos, or data you might care about from that account.
2. Sign Out of Devices: Sign out of this Apple ID on any active Macs, iPhones, or iPads via System Settings > [Your Name] > Sign Out. 
3. Request Deletion Online:

• • Go to the Apple Data and Privacy Page and sign in with your @mac.com Apple ID and password.
  • Select Request to delete your account under the "Delete your account" section.
  • Follow the onscreen prompts, choose a reason, and save the unique access code Apple provides (you need this code if you change your mind during the short verification/processing window).
  • Apple typically takes up to 7 days to process and permanently close the account.