In Word the CitaviWordAddIn.dot template was disabled and is now appearing in the Word options in the Inactive Applications Add-ins list. As a result, the Citavi Word Add-In is unavailable.
 
Solution
  1. In Word, click File > Options > Add-Ins.
  2. In the Manage drop-down menu, select Disabled Items and then click Go. Select CitaviWordAddIn.dot and click Enable
  3. Restart Word.