See this screenshot (route in Salesforce: Setup > Einstein > Einstein Activity Capture > Settings > Edit configuration > Field mappings):

enter image description here

I would like to add a mapping for the standard Event field 'Related To' (WhatId). But the '+ Add Field' button is disabled. How do I enable it?

2 Answers 2


I have dealt with frustrations configuring and customizing the EAC settings in the past and it is widely aware that the functionality is 'limited' in terms of configuration. While I am not 100% confident, I don't believe this is possible at the moment. While EAC will try to map the 'whoId', the WhatId field is also polymorphic (can be used for multiple object relationships) and I do not think it is supported (at least at this time) in the EAC Field mappings.

While the documentation is scattered I did find the following. It does not explicitly state that you can not, but I would assume you cant.

  1. Customize Field Mappings for Contact and Event Sync
  • You can’t customize mappings for standard fields that are used to match contacts and events during the sync process
  • Custom Salesforce fields aren’t used in mappings.
  1. Field Mappings for Event Sync

  2. How Events Sync with Einstein Activity Capture

While I was exploring something similar a while ago, there is a way to potentially create custom fields in outlook (with an admin) and sync those with selective SF fields. I think this may have been only for Contact sync. I had looked into alternative solutions such as capturing the data in a separate field and implement automation on the SF side (Trigger / Flow) to populate additional fields, but I did not end up implementing anything. Since this is a SF managed product, it is hazardous to add additional automation as it can break in future releases if SF changes anything, etc..

As to why the button exists but is disabled, I cannot concretely answer that. I imagine that if you hit the trash can icon near one of the other mappings then the add-field button will be activated but only to add the same field back (i.e, Description, Location, ...). If that is the case, it would most likely confirm that these are the only supported fields in the Event Sync Field Mapping configurations.

Best of luck, hope this helps


I found that by deleting one of the existing mappings, then the Add Field buttons becomes active. There must be a maximum number of mapped fields allowed.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .