I put in the wrong number for state identification number. Can I change it now?

If you have already filed your tax form, it will be a waiting game. The IRS does not open until February 12. Once it opens, it will reject or accept your return. The IRS should accept the W2, if the federal id is correct.

Next, the state of Maine will choose to accept or reject your return. They may accept your return with a wrong number but it will not cross check for tax withheld. You may receive a letter from the state stating the tax withheld is not verified. You would then mail them a copy  of the W2.

If your return has not been filed, you can correct it on the W2 screen.

If your return is rejected, you can correct the W2.