Aoxomoxoa

Recently I updated my Mac software to Mac OS Sierra, and my Logic X software to 10.3.1. Since doing this, whenever I plug my guitar into Logic, using my iUR2 audio interface, the guitar pre-sets which I regularly use sound incredibly out of tune and there are many popping sounds which appear. I've been using this set up and the guitar sound pre-sets for over a year and I've never had any problems, but since updating I can't get a clear sound. Has anyone else had this problem? Thanks, Alisdair