I have installed LR CC on a laptop.
The main computer was already synchronized with my iPhone via CC Cloud.
After connection to CC Cloud on the laptop, all the photos from the cloud disappeared.
I would have thought the photos would synchronize with the laptop.
But it is the contrary that happened.
The empty library from the laptop emptied the Cloud.
How to avoid this.
You can have photos from one catalog synced to CC at any time. Also the sync works from a computer desktop or laptop running Lightroom CC to your mobile devices iPhone, iPad, Android Smartphone with Lightroom Mobile App.
Sync does not work computer to computer.
You will need to turn off the sync on your laptop and re-sync from your main computer.
Actually it is One catalog from One Computer. Even if you copy the same Catalog file to a different computer and Sync it up with LT Mobile it will Un-Sync the other computer.
LR Mobile is not for syncing up more than 1 computer. It is to sync multiple iOS/Android devices to 1 catalog on 1 computer.