When working with any Data Source, you will need to ensure that you have the same fields available each time you access the data. This is particularly true of data sources that allow you to import multiple participants/attendees per transaction. Most notably Data Sources Qgiv, Eventbrite and SalsaEngage, although any data source that allow you to select how many event attendees, event purchases, etc. you want to bring over.
For example, if we were working with a template in SalsaEngage and built the template with two attendees (data source selection shown below), then we would have data fields in our mapping for Attendee 2.
A sample of how this could be mapped for a Guest attendee can be seen below:
However, if we were to open this template with the above mapping for the Attendee (2), but only selected 1 Attendee as the '...maximum number of attendees expected per transaction', all of the fields for Attendee (2) would no longer exist in the template. When that happens, you will see a warning that you are missing mapped fields (it looks something like the screen below).
If you Click OK, you may remove those fields from the template permanently.