How do I insert values into a multi select picklist field using MassEffect?
To load multiple values into a multi select picklist field simply separate the values in the spreadsheet with a semi colon:
If the exact same value(s) should be added to all the records being updated the "Add Constant" option (right click on the field to access the Add Constant option) can also be used to hard code the new values.
To merge the new values with existing values in Salesforce (vs. overwriting the existing values with the new values), right click on the "blue" mapped field and select the special update option "Merge input data with existing values in Salesforce".
A formula can also be written in MassImpact to merge new multi-select picklist values with existing data.