Computer Backup

Every time I backup my iPhone 6 plus and it finishes the backup it immediately say "your iPhone has never been backed up to this computer!" This is bull because I JUST FINISHED BACKING IT UP! This has happened constantly since upgrading to windows 10 with the iPhone 5s and my iPhone 6 plus. I have to do a recovery of my OS every time to get my backups back.....then I back up again and close iTunes and a few days later the backups are gone again. What do you do about this annoying problem? I've uninstalled everything that's possible on my computer that would interfere with the backups.....If I uninstall anything else the computer won't run.