By Tom Herman 

What ever happened to my missing federal income-tax refund check?

If you've been wondering about this, a good place to start your search is by visiting the Internal Revenue Service website ( irs.gov) and clicking on "Where's My Refund?"

The IRS says refunds generally are issued within 21 days after the government receives your return.

There are many possible explanations for a missing refund check. For example, the government may have mailed your check only to have it returned as undeliverable because of an incorrect address.

In such cases, the IRS says it reissues checks once the taxpayer provides a correct or updated address.

"You can easily avoid an undelivered refund by choosing direct deposit," an IRS spokesman says. "Last year, more than three out of four refund recipients chose direct deposit."

But the wait can be significantly longer if you are among the millions of people who have filed an "amended" federal income-tax return using Form 1040X. That's the form to use for fixing errors and omissions in previously filed returns.

The IRS says it can take "up to three weeks" from the date you mailed your amended return for it to arrive in its system. Amended returns must be mailed. You still can't file them electronically.

Then comes additional waiting time for the IRS to process your amended return. The wheels of tax justice grind slowly.

"You can generally expect your amended return to be processed up to 12 weeks from the date we receive it," the IRS says.

To find out the status of an amended return, try clicking on the "Where's My Amended return" tool on the IRS site. That has the status of amended returns for the current year and up to three prior years, the IRS says.