iTunes does not recognize the iPhone or or the iPad Mini when I try to sync them.

iTunes does not recognize the iPhone or or the iPad Mini when we are trying to sync them. Running iTunes 12.3.1.23 with Yosemite 10.10.3. Message says phone is synced with iTunes using another profile on this Mac, but it's only synced with the current profile. Also, iTunes keeps crashing. Another symptom is that the Mac started importing the photos from the phone as if they had not been imported previously. What should I look at to troubleshoot this and get it to sync?