The Citavi Word Add-In is disabled in Word even though the template CitaviWordAddIn.docm appears in the list of enabled templates.
The antivirus program SAntivirus Realtime Protection Lite is installed on your computer. This software program published by the company Segurazo blocks the Citavi Word Add-In from being loaded.
The authors of My Antispyware characterize the software as a potentially unwanted program (PUP):
SAntivirus Realtime Protection Lite is a program that is advertised as anti-virus software. Its creators claim that SAntivirus can scan the computer, detect security threats, remove the malware found, and also protect the computer from infection. But, according to security researchers, this program belongs to the category of potentially unwanted programs (PUPs), since it is installed on a user’s computer as part of various freeware without the explicit consent of the user. Many computer users in various public forums reported that SAntivirus Realtime Protection Lite suddenly appeared on their computer and it won’t uninstall.(Source)
Usually you can only find out if the software was installed by opening the Windows Task Manager:
Image source: https://www.itexperience.net/services-and-controller-app-fix-segurazo-high-cpu-usage/
Uninstall the software by following the instructions at My Antispyware or ITExperience. The default Windows Defender program in Windows 10 already protects your computer making additional antivirus software unnecessary. See the How-To Geek article "What’s the Best Antivirus for Windows 10? (Is Windows Defender Good Enough?) for more information.