Unfortunately Mailchimp created a little hickup in the update 1.93.2 (2020-08-11) to their Salesforce integration. When you open the setup “MC Setup” you might be greeted with an error message:
“Read” permission to field “MC4SF__Prompt_For_Full_Sync__c on object “MC4SF__MC_List__c” is not allowed for the current user.
I had seen this on my Developer Edition org at first and contacted the Mailchimp support. Sadly it doesn’t seem to ring enough alarm bells, the final answer was “Since the error has a quick fix and it’s not causing an issue in all accounts, we will be keeping an eye out for further instances to see if there are any similarities.” It seems a bit strange to me, as this is breaking existing installations when the update is applied.
However, there is a solution. In the field level security settings of the field “Prompt For Full Sync” on “MC Audience” you have to give read access to this field for all profiles that will use the Mailchimp integration.
In “Setup” navigate to “Object Manager”
Then select “MC Audience”
And in Fields & Relationships select “Prompt For Full Sync”
Then go to the field level security and grant at least read permissions to all profiles that use the Mailchimp integration
It seems that “read” is all that is required, but I don’t know that for a fact.
I’m just astonished that this newly introduced field seems to be a necessity, yet the managed package does not provide any permissions for this field. Additionally I would have expected Mailchimp to quickly remedy this issue. Luckily for ConcisCons customers, I had seen that problem before they experienced problems with that.
Additionally, it seems that these missing permissions in a managed package is not a first for Mailchimp: the MC Setup page is returning an error