Go ahead and try the above approaches:
1. Delete contacts/calendar/notes from deleted items folder.
2. Sync w/ MS Outlook closed.
3. Change the "do not sync older than" option.
None of those worked for me, but if they work for you awesome! If not, here is how I fixed it for my situation:
I had nine conflict messages. Four were for calendar events, the rest for outlook notes.
1. I noticed that the four calendar events were quite old, so I deleted them from outlook.
2. Sync. Error was gone.
Had the error not cleared, the next step were:
3. Create a new copy of the five notes but with v2 at the end.
4. Sync. You now have v2s on both phone and pc.
5. Delete the originals.
6. Sync again. You should now have only the v2s and... no errors!
7. Rename the v2s to remove the v2s. They now look like the originals.
8. One last sync. No errors and everything should look good!
I am on windows 7, iphone 6 plus.
Good luck!