Answers.Body: <p>It was highly likely due to this issue which has now been fixed in 4.6.3:</p>
  
  <p><a href="https://issues.civicrm.org/jira/browse/CRM-16251" rel="nofollow">https://issues.civicrm.org/jira/browse/CRM-16251</a></p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-05-20T15:51:01.147Z
Answers.Text: Thanks as always for your swift response. That's got to be it. I'll schedule an upgrade. It looks like the client can avoid the problem in the short term by not using the preview or test message features?
Answers.UserDisplayName: fred2
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-05-20T15:40:33.063Z
Answers.LastActivityDate: 2015-05-20T15:40:33.063Z
Answers.UserDisplayName: Donald Lobo
Body: <p>On a well established site that uses CiviMail and Groups for a range of mailing lists, a message was sent out this morning as usual to a list of over 1400 people.</p>
  
  <p>Inexplicably, each recipient received the mail 4 times. I have checked and the message was definitely only queued once, and was sent out by a single cron job. The report for the message makes clear that something very odd happened:</p>
  
  <pre><code>Intended Recipients 1411
  Successful Deliveries   5644 (400.00%)
  Tracked Opens   268
  Click-throughs  50
  [...]
  Scheduled Date  May 20th, 2015 9:48 AM
  Status  Complete
  Start Date  May 20th, 2015 10:00 AM
  End Date    May 20th, 2015 10:11 AM
  </code></pre>
  
  <p>Normally a cron such as this takes about 2 minutes to run. This one took substantially longer.</p>
  
  <p>The CiviCRM installation was upgraded to the latest version on May 4th, however multiple messages have been sent successfully in the interim.</p>
  
  <p>I cannot see any evidence of user error which would have caused this to occur.</p>
  
  <p>Greatly appreciate any thoughts on how this came about, as the site owners are naturally reluctant to use the system again until the cause has been established.</p>
  
Tags: <civimail><email><contacts><groups><cron-job>
Title: Possible cause? CiviMail sent "400%" of queued messages, hit each recipient 4 time
ThreadText: # Possible cause? CiviMail sent "400%" of queued messages, hit each recipient 4 time
  
  (Asked by: username_0 on 2015-05-20)
  
  On a well established site that uses CiviMail and Groups for a range of mailing lists, a message was sent out this morning as usual to a list of over 1400 people.
  
  Inexplicably, each recipient received the mail 4 times. I have checked and the message was definitely only queued once, and was sent out by a single cron job. The report for the message makes clear that something very odd happened:
  
  ```
  Intended Recipients 1411
  Successful Deliveries   5644 (400.00%)
  Tracked Opens   268
  Click-throughs  50
  [...]
  Scheduled Date  May 20th, 2015 9:48 AM
  Status  Complete
  Start Date  May 20th, 2015 10:00 AM
  End Date    May 20th, 2015 10:11 AM
  
  ```
  
  Normally a cron such as this takes about 2 minutes to run. This one took substantially longer.
  
  The CiviCRM installation was upgraded to the latest version on May 4th, however multiple messages have been sent successfully in the interim.
  
  I cannot see any evidence of user error which would have caused this to occur.
  
  Greatly appreciate any thoughts on how this came about, as the site owners are naturally reluctant to use the system again until the cause has been established.
  
  **Tags:** civimail, email, contacts, groups, cron-job
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-05-20. Score: 3 | Accepted answer
  
  It was highly likely due to this issue which has now been fixed in 4.6.3:
  
  <https://issues.civicrm.org/jira/browse/CRM-16251>
  
  > **Comments:**
  > **username_0**: Thanks as always for your swift response. That's got to be it. I'll schedule an upgrade. It looks like the client can avoid the problem in the short term by not using the preview or test message features?  
  
  ---
  
  