Import Data through Excel successful even with mandatory field missing

Hello everyone,

we are doing some tests in CRM Online 2016 and currently we are testing the data import wizard.

We noticed that if in the Excel files we fill the columns it will import the record correctly with each and every field filled, and this is as expected.

But, when we tried to import a record that has some mandatory field left empty, for instance if we import a lead without first and last name, it will be imported instead of beeing rejected.

Is there any customization to take or some setting to set?

Thanks in advance