Do you have galaxy watch or some other samsung accessories? It appears when content or apps are updating automatically. or Some updates(accessories updates)might have gotten corrupted because they didn't install it correctly. That's why your phone is continuously showing transferring files to your accessories or accessory. So just check for recently installed updates and reinstall them. After this reboot your accessory and also restart your phone.. just give a try..
Then follow what I wrote ..there must be some updates or apps which didn't install correctly, so find out those apps or updates and reinstall them properly.
