iTunes to iPhone Sync Problems

I have iOS 10.2 (iPhone SE) and just updated iTunes to 12.5.4.42 (windows 8.1) and I'm now unable to sync at least ~112 songs to my iPhone. The sync simply stops during Step 7 of 7 and won't either disconnect the phone or continue syncing regardless of pressing eject, stop sync, etc.. The songs appear as greyed out in the list of music on device (on both iTunes and iPhone) and have a dotted circle icon. I've reset both PC and iPhone and logged out/in of iTunes Store. I tried deleting some of the grey music from the Library and re-adding it but the sync is still stopped. This is the first time I've had this problem. Is it something to do with the new updates or copyright or is it a setting I'm missing?