Admin does not have the option 'Manage Unsent Emails'.
Reproducing the Issue
Go to Admin> Tools.
Workflow 'manage unsent email' has not been added to the admin's role.
1. Go to Admin> Security> Role Management.
2. Search and edit the admin's role.
3. Click on Workflows tab.
4. Add one or more from the list.
5. Expand All and add for 'manage unsent email'.
manage unsent emails, purge emails, admin cannot purge emails, delete unsent emails , KBA , LOD-SF-LMS-ADM , Admin Tools , Problem