What should I do if I received another W-2, or have discovered an error on my return after I filed?

If there is a change to your adjusted gross income or the allowable exemptions on your federal return, Michigan law requires the filing of an amended return.

Beginning in tax year 2017 you must file an MI-1040 with the amended box checked and a completed Michigan Amended Return Explanation of Changes (Schedule AMD). Include all applicable schedules used to calculate your Michigan return (even if included with your original return) and supporting documentation to substantiate the changes made on the amended return (e.g. federal return and schedules, property tax statements, W-2s, amended Schedule W). The amended return can be e-filed.

To amend tax years 2012-2016 file an MI-1040X-12.  You must provide an explanation of the changes on page 2.  Include all applicable schedules used to calculate your Michigan return (even if included with your original return) and supporting documentation to substantiate the changes made on the amended return (e.g. federal return and schedules, property tax statements, W-2s, amended Schedule W).  The MI-1040X-12 cannot be e-filed.

Failure to include an explanation with supporting documentation for the changes made will result in a denial of the return.