TurboTax customers may be scrambling to file before the April 15 IRS deadline after the online tax software company went offline briefly Sunday.
Users immediately reported problems and left angry Twitter messages for the company.
"Can't log in. Get message that says Missing Security Question. been in and out of my account all day - this is new," user H J McAllister tweeted.
"U cant! Not now!! #epicfail" tweeted user Emily Gunsberger.
TurboTax responded quickly and got the site running again but more than half of all individual tax filings online are made through the company.