There may be special software that could dig remnants from that formatted drive, but I would say it's a lost cause.

It's quite common to remove old hard disk and connect to new computer even as an external drive. The main purpose of the inital connection being to copy important files over to the new drives on new computer. But it sounds like you omited to do this before reformatting. There are products which claim they can help, but I cannot verify anything. Take a look at the following : https://www.easeus.com/ad/format-recovery.htm https://techcommunity.microsoft.com/discussions/windowsinsiderprogram/how-can-i-recover-files-from-a-formatted-hard-drive/4394383 Without any recovery Address books would be lost, but whether you can still have emails depends upon whether you have emails on server. If you used IMAP accounts previously then all data/emails should still be on the server. Create a new existing mail account for email address and set it up as imap account. Then you can subscribe to see various folders on the server. If you used Pop accounts then maybe many will still be on server. It depends upon whether you set previous account to 'Leave messages on server'.