title: Why does CONVERT to datetime break for this query but not the other?
body: <p>This query works fine:</p>
  
  <pre><code>select CONVERT(DATETIME, GroupAdminEffectiveDate, 101) from ExchangeSmallGroupEnrollment
  group by GroupAdminEffectiveDate
  </code></pre>
  
  <p>and returns the following:</p>
  
  <pre><code>1900-01-01 00:00:00.000
  2012-06-30 00:00:00.000
  2012-07-01 00:00:00.000
  2012-07-11 00:00:00.000
  2012-07-23 00:00:00.000
  2012-07-25 00:00:00.000
  2012-08-01 00:00:00.000
  2012-08-14 00:00:00.000
  2012-08-26 00:00:00.000
  2012-09-01 00:00:00.000
  2012-09-03 00:00:00.000
  </code></pre>
  
  <p>However, the following query:</p>
  
  <pre><code>select CONVERT(DATETIME, GroupAdminEffectiveDate, 101) from ExchangeSmallGroupEnrollment
  </code></pre>
  
  <p>and I get the following the error:</p>
  
  <pre><code>Msg 241, Level 16, State 1, Line 1
  Conversion failed when converting date and/or time from character string.
  </code></pre>
  
  <p>Any ideas? Much appreciated.</p>
  
  <p>UPDATE:</p>
  
  <p>Query:</p>
  
  <pre><code>select distinct GroupAdminEffectiveDate from ExchangeSmallGroupEnrollment
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>(empty string)
  06/30/2012
  07/01/2012
  07/11/2012
  07/23/2012
  07/25/2012
  08/01/2012
  08/14/2012
  08/26/2012
  09/01/2012
  09/03/2012
  </code></pre>