Stumbled upon this issue yesterday. Found a lot of blog and forum posts on the Internet but nothing helped. Here’s my 2 shekels.
What happens is this. If I install Outlook for iOS on a phone that’s not enrolled into Intune, I am able to save contacts. In this case the app protection policies apply, and I can either save contacts within Outlook itself or do this toggle to have it saved in the Contacts app too.
Then I go ahead and enroll this phone. I get a warning saying Outlook is now going to be managed:
And after that if I create a new contact in Outlook it silently fails. The contact is not saved to the Contacts app. Interestingly, I can’t toggle the setting to OFF and save contacts in Outlook itself – which was odd.
This also does not impact Android devices.
After a fair bit of Googling and poking around, I realized it was the following setting in the iOS configuration profile: “Allow managed apps to write contacts to unmanaged contacts accounts”
It was set to Not configured (the default), which looks like it leaves it to the OS, so the correct thing to do is set this to Yes.
For a while I thought it might be related to another setting – “Allow unmanaged apps to read from managed contacts accounts” – but turns out to not be the case. Best to set this one too to Yes I suppose, so the iOS contacts app can see what’s in Outlook. I guess if this is set to Yes, then Outlook doesn’t need to save contacts to the iOS contacts app as the latter can read directly from Outlook? Am not sure, and I didn’t test further…