Solution: You need a C2R specific repack. Most repacks today are universal, but if you see this error, search for "Office 2016 C2R Croatian LP repack". Alternatively, convert your Office installation from C2R to MSI using third-party tools (advanced).
Because repacks are modified by unknown third parties: microsoft office 2016 croatian language pack repack
Mitigation: Run the repack inside a Windows Sandbox or virtual machine first. Monitor network traffic using TCPView. Only download from community-vetted threads (e.g., MyDigitalLife, Ru-Board). Solution: You need a C2R specific repack
After installation:
Result: Your ribbon, right-click context menus, and dialog boxes should now be in flawless Croatian. Mitigation: Run the repack inside a Windows Sandbox