In the spring’15 release, Salesforce introduced Middle Name and Suffix under the Contact object to avoid confusion between two records with the same first name and last name. To turn on this feature, you will need to contact Salesforce support. Both fields also support data import.
For further details, check out the release notes for Spring’15.
If you are trying to import data into middle name field but somehow the field is not showing in your data loader mapping list. What should you do?
- If you are using apex data loader, make sure that your data loader version is the latest. The field will not show in the older version.
- Make sure that the field is available in Salesforce. If you are using Professional edition, make sure that it is displayed in the layout.
- If above method does not work, try using any 3rd party import tool. ie: dataloader.io.