Is it possible to recover an email that has been clicked on "delete forever" in the trash folder? I have accidentally clicked delete forever for an email but now I need to recover it.
Unfortunately, there isn't an easy way to recover deleted email once you've done it forever.
The other answer on here is right - if you used another tool it might be possible.
Another option that might work (but is less likely), is to fill out a report of missing messages for the Gmail team to process: https://support.google.com/mail/bin/bin/request.py?&ctx=bugflow_receive31&contact_type=bugs
Gmail's help article says:
If you've deleted a message permanently, by clicking Delete Forever in your Spam or Trash, you won’t be able to recover the message using the Gmail interface.
But you could use that bug request tool to describe directly to the team which email message(s) you need to recover and they might be able to help. Since this is meant for accounts that have been compromised, it might not work, but it's worth a shot.
Good luck :)
If this Gmail account was part of a work or school Google Apps domain, your admin can restore deleted email or Drive files for up to 25 days by following the step provided in this Google help article: Restore a user's Google Drive or Gmail data
This does NOT apply to consumer @gmail.com accounts.