Neither makes a difference. It won't allow Google Music to sync music to the cloud whether you use the website itself, or the utility that can be installed on your PC. I tried disabling web protection, and real time, and both at once. None of these made a difference, it still can't connect or sync. Thanks for trying to help! Sorry, didn't see that you replied until just now!
Edit: Just to confirm it was related to ESET Smart Security, I did try uninstalling ESET. Google Music then worked fine. Reinstalled, and it was back to issues. It also causes issues with Google Photos. It will always hang and give an error with "2 photos left" to upload, but always completes when ESET is uninstalled. This is less bothersome however as if you go to the site itself, photos work fine where music does not. For photos ESET only seems to interfere with the utility.