What does it mean Federal refund transmitted

[VolvoGirl]

When you efile you get back 2 emails. The first email only confirms the transmission. The second email says if the IRS (or state) Accepted or Rejected your efile. 

[Jmfrei1]

How long after it’s been transmitted will it take to be excepted or rejected? I filed back on the 16th and it was held until today I know they just started excepting them today I got the transmitted update already....