Most often this occurs when a sync was unable to be completed. If more than 24 hours has passed and the message is still displaying in your Scheduler, please Chat With Support and reference this article. 

Please provide the following information:
  1. Current Sync Number
  2. Date of your last successful sync
  3. A screen shot of your Log Tab
  4. The log files on the server for the last successful sync and the failed sync (Traditionally, these are stored in a path similar to C:\Program Files\Blackbaud\The Raisers Edge 7\Custom\Service\Data\logs)