Can you refile taxes from pervious years if you forgot something?

[Goldy1]

Dh has done our taxes for the past few years.

He realized today we may be able to fill out the 1040 CR for Michigan to get a tax credit(money back to us) for paying our property taxes and some medical premiums while doing our 2008 taxes.

He redid the form for the past 8 years and realized that we were qualified to get the credit for 6 out of the past 8 years, but he did not know and did not file this form. The total would have been $1700 we missed in credits varying from $120 to over $400 a year in credits we were not paid due to not filing the from.
thanks

[poundwise]

You will not be able to go back eight years. For missed deductions or credits, you have three years from the original filing deadline to file an amended return seeking an additional tax refund.

IRS: Tax Topic 308

"...to claim a refund, Form 1040X must be filed within 3 years from the date of your original return..."

[backtaxpro]

If this is to get a state refund from Michigan than the IRS rule will not apply. Each state has their own laws and regulations regarding taxes but typically eight years is too far back with most states. I would check with a Michigan tax professional for doing anything else.