Unsent mail is stored in your drafts folder, or your outbox depending on your e-mail client. To recover the drafts or outbox folder, and the e-mails within it, you can import your most recent e-mail backup file. If your last backup file was created before you wrote your unsent e-mail, it won't be in there. If you accidentally deleted your unsent e-mail, it's probably still available in your hard drive's "dumpster." Outlook has a built-in recovery program that can recover e-mails from the dumpster. Commercial software is also available to recover e-mail files.
Open the "Deleted Items" folder in your e-mail program to see if your unsent e-mail is still there. If it is, just drag it to the inbox or other folder to recover it. If not, try the built-in dumpster recovery program.
Click on the "Tools" menu to find out if your e-mail client has a file recovery program. In Outlook, click on "Recover Deleted Items...." You can also search "Help" to find out if your program has a similar option with a different name.
Look through the list of deleted items that appears. Select the unsent e-mail you want to recover and click on the "Recover" icon above the list. If you don't see your e-mail file listed, you may need to try commercial recovery software.
Items that have been deleted will sit in the dumpster until they're written over by new data. If your unsent e-mails were deleted recently they should be recoverable using the built-in or commercial recovery software.
Read several reviews before deciding on a commercial software option. Purchase and download recovery software from a reputable, well-known retailer or website.