It depends on which feature is doing the update and which direction the data is travelling. Field mappings and the import wizard treat a blank Salesforce value differently, so it is worth knowing which one you are using.

Salesforce to Campaign Monitor

Field mappings:

A blank Salesforce value always clears the mapped Campaign Monitor custom field. This applies to every field type, including text, number, date, picklist and multi-select picklist fields, and there is no setting to change it. The update is sent the next time the contact or lead is saved, or when you run a retrospective sync from the field mappings screen.

Import wizard:

By default a blank Salesforce value is ignored, so the existing value in Campaign Monitor is kept. To have blanks clear Campaign Monitor, edit the import, go to the scheduling step, expand Advanced and enable Clear blank values. This applies to all mapped fields in that import, not only picklists, and takes effect the next time the import runs.

Note: A number of 0 and an unchecked checkbox are not blank. They are sent to Campaign Monitor as "0" and "false".

Note: If you run the import wizard as a safety net alongside field mappings, enable Clear blank values on the import so both features treat blanks the same way.

Campaign Monitor to Salesforce

A blank value in Campaign Monitor will not clear the mapped Salesforce field. Campaign Monitor does not return empty custom fields when we request subscriber data, so the sync cannot tell that a value was removed and Salesforce keeps its existing value. There is no setting to change this.

For picklists, the workaround is to add a value such as "None" in Campaign Monitor that can be selected, so a value is always returned.

Related Articles

• Field Mappings [Full Guide]

• Can I map data in both directions?

• Why are my field mappings not updating Campaign Monitor?