The Sent Items folder is a search folder in Outlook that allows you to get information on all email that you have sent from your account on the Outlook email system. You may lose the sent items folder if you click and drag it out of the Outlook window or choose the delete option accidentally. This is the process to restore your sent items folder:
Click on Tools > Find.
The find window will open, click on the Advanced Find button.
The advanced find window will open.
Click on the first drop down list box and choose the All Fields option.
In the window that opens up choose the Item Source option and click OK.
In the second list box choose the = option.
In the third list box choose the Sent option
Then click on OK in the Advanced Find window.
Now click on OK in the Find window.
A find results window will open.
In the results window click on the File menu then Save As Folder.
Name the new folder Sent Items and place it in the position you want it to appear in your Folder List.
Click on the Finish button and close the find results window.
You should now see the Sent Items folder back in your Folder List.