Syncing iPhone 6+ creates "other" data

Question

I am using an iPhone 6+ (version 8.1.3) with the latest version of iTunes.  I recently tried to sync my iTunes library to the phone, but none of my new music transferred (the song list on the phone has the songs, but they are grayed out, implying that they did not actually transfer).  I tried syncing again, which sat for an extended period of time before I cancelled.  Now, all the iTunes material on my phone (all the previously synced music, TV shows, etc.) shows up as "Other" data within iTunes.  I have restarted both the phone and the computer.  Since all this material shows up as other (roughly 30 GB on a 64 GB phone), iTunes thinks that I am trying to add an additional 30 GB of data to the phone and the sync fails.  This is a problem that I have had with my old iPad (2nd gen) for over a year now, but it only recently happened for the first time on the phone.  The only way I could fix the problem on the iPad was restoring and setting up as a new iPad, which was time-consuming and extremely annoying (it also happened during every single sync, which basically means I don't try to add new stuff to my iPad anymore).  Is there a better way to fix the error?  Thanks in advance.

Answer 1

O.K. I may have fixed it (time will tell).
As I had previously chosen to sync with Microsoft Outlook 2010, but the trial period expired and the price to but it was far too high, so I changed to Syncing with Gmail. Therefore I wondered if Outlook may be affecting the iTunes sync even though it was not current chosen in iTunes contact sync option. So, I un-installed Microsoft Office 2010 and re-booted the PC. Now, pressing the 'Rest Sync History' button in iTunes no longer created new contacts in Gmail.
However, this did not completely solve the problem. With 0 contacts on the phone, and 0 contacts in Gmail, syncing the phone still re-created 41 of the previous contacts. Thew only way I could get rid of these 41 contacts was to deleted them one at a time from the iPhone itself. Doing it from Gmail, or un-checking the iTunes 'sync contacts' option to delete all contacts from the phone at once, did not work; the contacts still kept coming back.
Funny thing though, iTunes did indicate that it would add 41 contacts when I synced the phone to the computer, but after deleting them from the phone it now warned that it would delete 41 contacts from the computer. But, these contacts were not in my Gmail, so I still don't know where they were coming from.
Either way, after many hours spent over many days, I seem to now be able to sync my phone contacts with my Gmail without it creating any more unnecessary duplicates.
I hope someone out there can tell me why this happened, and I hope my experiences with this help someone else in a similar situation.
- James.
Message was edited by: jal741