As Lightroom is not able to import your CR2 files, could you please let us know which version of Lightroom are you using and you can check the link below to make sure that your camera is compatible with the version of Lightroom you are using.
Version von Lightroom: 6.0 
Betriebssystem: Windows 8.1 Business Edition
Version: 6.3 
Hope this can help you...
The Camera ist EOS 5 D Mark IV and it works before i use the new update.
Thank you for providing the information.
Canon EOS 5 D Mark IV is compatible with Lightroom 6.7 or above so please update your Lightroom through the creative cloud application.
Can not find the update link to 6.7....
update to 6.10 doesn´t work....