It sounds like you should be using Auto Import rather than Tether.
The EOS 5D is not supported in Lightroom CC - Lightroom 4.2 and earlier were the supported versions for that camera.
If you are using File>Auto Import then your 5D is supported provided you are using something like the EOS Capture Utility to do the ingestion of the images into the folder you've designated. Auto Import requires you to specify a folder to Watch (that folder must be empty to start) and a destination folder for Lightroom to use to deposit the images.
Create a clean empty folder and point Canon's EOS Utility there.
Launch Lightroom and go to File>Auto Import>Auto Import Settings.
Specify the folder in the first step as the Watched Folder
Specify the Destination folder - click [ OK ]
Go back to File> Auto Import - Enable Auto Import.
Go back to your EOS Utility and snap a picture.
It should go to the Watched and then disappear and then appear in the destination folder. Lightroom should show the photos in the destination folder in the Folder's Panel or in the Previous Import system collection in Catalog panel.
Thank you very much. If i work like this, it works.
But I made a mistake in my message, i work with a canon eos 5D mark III en normally i can Tether with this camera. On the way you describe it works, but not just with Lightroom.
It sounds like you are attempting to use EOS Utility and Lightroom simultaneously.
You should only use Lightroom and not have EOS utility open when tethering into Lightroom.