First, make sure you're updated to 11.1 (2015.1)
Some people find a bug with the Creative Cloud libraries causes a lag and doing what this article recommends helps some people:
Other people find that going to File Handling preferences and setting the number of recent files to 0 helps.
Hey Steve, Thanks for the response. I've set recent files to 0 and killed the libraries. It seemed to work for about 30 seconds and then slowed down again. This is killing productivity.