Q: Backup fails after replacing iPhone5s with replacement 5s.

Had to replace my 5s with a replacement 5s. Now when I sync get error, "iTunes could not backup iPhone "phone name" because backup could not be saved on this computer". I have almost 60gig free space and other devices sync and backup fine. iOS 8.2 syncing to Macbook Pro running 10.9.5.

Thanks for any suggestions.