This can happen when running an acknowledgement that has multiple packages and the packages use different export definitions.  You can still send out these emails, or print out the word documents for mailings by following the steps below.
  1. Go to marketing and communication
  2. Click on membership renewal efforts
  3. From the membership renewal effort click the hyperlink to your renewal effort
  4. From the task bar select view export status
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Then: 
  1. On the recent status tab under export out puts click the expand button next your first package
  2. From here you can start email job or down load each output
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