Some 6 million returns from last year have yet to be processed. Delays could snowball for seasons to come.
In a statement Monday, the agency warned that it is still addressing a backlog of taxpayer inquiries from the past year.
For a lot of people, the last year has been weird, from a tax standpoint.
"Americans need cash now," Treasury Secretary Steven Mnuchin says at a press conference.
The IRS is trying to modernize its computer systems and improve customer service — with a smaller budget and workforce.
With so many changes to the tax code, people like Evin Moore are using experts.
The "free file" program is controversial because it's run by the same private companies that make money on tax preparation.
Fear of costly mistakes drives some taxpayers to use a professional or software.
It's the first filing season under the tax overhaul of 2017. Software companies are still catching up.