You'll see the following error message in H&R Block’s 2017 tax software if you have entered the characters C/O before the name of the person receiving your mail in the In care of field:

The In Care of name entered can’t include the characters C/O. Please correct your entry. [error code: 179]

How do I fix this?

To correct the error, enter only the name of the person authorized to receive mail on your behalf in the In care of field on the Your mailing address page.

Correct format: John Smith
Incorrect format: C/O John Smith