When you do an import, you may have to format data to suit the property's field type. For importing data into a checkbox property, you can import values to a multiple checkboxes property and to a regular checkbox property.
Add values to a multiple checkboxes property in an import
To add or append value(s) to a multiple checkboxes property in an import, add a semicolon before the first value, and then, between each additional value (;value 2;value 3; value 4) in your import file.
For example, if you have a Product property and a contact already has a value lawn mowers for it, you can import additional values to the property for that contact by including the following in the Product column of your CSV for that contact:
Add values to a single on/off checkbox field in an import
In the import file, create a column for the single checkbox field and set the value on each line to:
True or Yes, to display as Yes or checked in HubSpot; or
False or No, to display as No or not checked in HubSpot.