Each bit field type maps "1" and "0" to two valid string values.
To make sure your records import, do one of the following:
More information: Work with Data Maps.
Bit value mapping and importing is not case-sensitive.
If you use a Import Data Wizard to create a new bit type field, data only imports as "True" or "False." Your source data must use a "1" or a "0" for those values and not text strings (such as "True" or "False"). After importing your data, you can customize the new bit field to change the values to text strings. Create any new required bit fields, and then use the Import Data Wizard to import data to the field.
Suggested Preparation in Source Files
To avoid import errors, make sure that the values for bit fields match the existing values in Microsoft Dynamics CRM, or manually edit the import data map to map your values to valid Microsoft Dynamics CRM values.
Use the Import Data Wizard to Map Option Set Values
Use the Import Data Wizard to map the values in a source columns to the values of a Microsoft Dynamics CRM field. Define the lookup mapping on the Map Fields page of the Import Data Wizard. More information: Import records from a file
Mapping in the Data Map (optional)
To map bit values in a data map, create a <PicklistMaps> section. See How List Values Are Imported.