Launch MFCMAPI | Click Session | Logon and Display Store Table
Choose Outlook profile | Double Click on Mailbox - username items
Expand Root Mailbox | Expand IPM Subtree | Click on Sent Items |
Look for properties named "PR_ATTR_Hidden,PingTagAttributeHidden,ptgAttrHidden and verify the "Value" is "false/true"
True = Sent Items folder is hidden
False = Sent Items folder is not hidden.
If the value is "TRUE" | Double click on it | It will open PropertyEditor

Start -> Click Run -> type "Outlook /resetfolders"

After run above command restart the outlook and u will see the Sent Items folder. If Sent Items folder not available , check any Untitled folder is available. Then rename the Untitled folder name into Sent Items folder using MFCMAPI tool