MN: Getting the following error even though the number entered is 7 digits long: Schedule M1W 1: Line 1-Payer's 7-digit MN state ID number-3 must be 7 digits long.

The invalid number was imported from a Paylocity W2.  It came into the number field with "MN" and a blank space leading the number.  The error message did not show this, but when checking the W2 form itself in Turbo Tax it was visible.  Removing the MN and "space" fixed the issue.

How do you go fix this? It won't let me make any changes when I'm looking at the form.

Removing the MN and space did not work for me.  It is still asking me to enter 7 digits, even thought it already is 7 digits.

If need be, delete the W2 and reenter it manually.  That may get rid of the diagnostic.