When we delete an email on our Apple it does not show in the deleted items. Are they lost forever?
You can try go to yesterday history and can search it. Or, it is better to fine software which can help you a lot. Such as MiniTool Data Recovery
You may try some recovery software such as MiniTool Mac Data Recovery, which I'm using for years, and worked every time I need it. Good luck!
If you're using TimeMachine, that keeps the state of your e-mail. Simply enter TimeMachine when mail.app is in front. All your old e-mails will be there!
try using a recovery software...as mails in mac are stored on your hard disk it should work...
You may want to check to see that the mail hasn't been archived. Try looking through the All Mail category. And of course, you can always check the email provider's site (i.e. Gmail.com, mail.yahoo.com, etc.) and I'm sure you'll be able to find the email there.
Have a look at this link and let us know if it helps:
Once emails are gone in Apple Mail (including out of the Trash folder) they are pretty much gone.
You can try data recovery software e.g. TestDisk or Data Rescue but my experience is discouraging at best. With only 20 minutes (in idle) between deletion in Apple Mail and using Data Recovery software we got maybe 1% of over 5000 mails back while it took several hours to perform.
And as always, the more you use the computer in-between the lower the chance of recovery.
First make sure that within the Account settings you set to "Move deleted messages to the Trash mailbox" and you set "Permanently erase deleted messages when" to "never".
If all of this is set you might be lucky and the mailbox is just corrupt. You can check whether there are mails in the Trash by going into "/Users/yourname/Library/Mail/V2/Mailboxe/Trash.mbox" and look through the subfolder(s). The easiest way is to use the Finder menu "Go", then press ALT to make the Library show up and select it.
If there are mails in there copy them to your Desktop or make a backup somewhere else. Then within Mail select the Trash folder and at the top menu click "Mailbox > Rebuild".