Use the mass email queue to view the status of scheduled mass emails and cancel mass emails if necessary.

To view the mass emails you have scheduled, go to your personal settings and select Email | Mass Emails or Email | My Mass Emails. If you have permission to view all mass emails in your organization, from Setup click Mass Email or Monitoring | Mass Email.From these pages, you can:Click Cancel to cancel a pending mass email.
Click Stop to stop a mass email that Salesforce is in the process of sending.
Click Del to delete the record of a sent or canceled mass email from the queue.
Click the name of the mass email to view details about an individual mass email.The mass email queue shows the number of recipients that the mass email was addressed to and sent to. These numbers may differ because:The mass email would cause your organization to exceed its daily mass email limit. Salesforce does not send the message to any of the intended recipients in this case.
One or more selected recipients opted out of receiving mass email after the mass email was scheduled but before it was processed.
One or more selected recipient email addresses were removed from the contact or lead after the mass email was scheduled but before it was processed.
The user who sent the mass email was deactivated after the mass email was scheduled but before it was processed. Salesforcedoes not send mass emails scheduled by a user who is deactivated.