How to add App Group entitlement to existing, sandboxed app?


I am trying to test, whether I can add App Group entitlement to an existing app.

I have created a new App Group Identifier in the App Developer account:
I have a feeling that this is already, where I go wrong. I might have to use a team identifier
Then registered it in the identities for 2 existing Apps
Then added the entitlement in Xcode to the App Code
And my created App Group Identifier is not offered for selection, which cannot be good
Then followed the following guidance for testing:

And keep getting errors in the primary app:
One is a spurious one from what I googled
But then there are lots of warnings that the Menu outlets cannot be connected to the NSUserDefaults
And of course, nothing is written into the App Group Container.

I used this link: to help me understand the initial steps of registering.

My questions please:

  1. is it not possible to add App Group entitlement to an existing app?
  2. is there anything obviously wrong in my above approach that prevents success?

Thank you for your help!


Just to say that I opened a developer ticket and got it sorted.

It does not seem to be of great interest to anybody as nobody answered, but if anyone wants help then just post to this forum and I will post the syntax that worked for me.

Best wishes