Word was started as an administrator and cannot communicate with Citavi as a result.
  1. End Word.
  2. Switch to the installation folder for Word and right-click the Word icon. Word 2013 is normally located here: C:\Program Files (x86)\Microsoft Office\Office15\Winword.exe
  3. Select Properties.
  4. Click the Compatibility tab.
  5. In the Privilege level area clear the Run this program as an administrator checkbox.
If the option is not selected, check the same setting for Citavi.
The installation folder for Citavi 5 is C:\Program Files (x86)\Citavi 5\bin and for Citavi 4 it is C:\Program Files (x86)\Citavi 4\bin.