I use Sony Xperia Z3+ with Android 5.02. The above advice won't help. I keep getting the "Unable to edit read-only contacts"
All in all I am very disappointed with Microsoft's pseudo-support and advice that do not offer real help but just intimidate people and insult everyone's intellect giving an impression that the fault is in the user who is just too stupid.
Now I have to use Sony's app that transfers my contacts from the old Windows Phone to the Sony. Guess what cloud service I am going to use then?
Right, Google of course. This way Microsoft is only losing users who could be valuable also to them. Ironically, they are losing them to the worst enemy, Google.
I would have expected Microsoft to learn something from being so arrogant with the Windows phones. But no, the old legacy lives on. However, the days of Microsoft being the only relevant provider of services and software are gone forever.
There is a lot of good in MS products, and that is why I keep hoping the attitude to change. Were it otherwise, I could not care less.
Have a good day!
Jouko