AppData CoreSync cloudnative taking up 17 gigs on hard drive

Help! I was storing my files on the cloud, but after speaking with an Adobe support specialist, they explained to me that much of the data is not actually fully on the cloud, and many of my file information (Photoshop) is stored on my local drive also. I have since moved all my files off the cloud onto an external hard drive. 

I am constantly full on CPU and data on my hard drive, and using TreeSize, I found that I have almost 17 gigs of data with this AppData Roaming CoreSync folder. What the heck is in here and can I get rid of any of this data? Or at least stop it syncing without losing any of my library data (colors and color themes mostly).