IRS issues several notifications to the transmitter during the various stages of Modernized e-File (MeF) processing. If a taxpayer uses a third party transmitter to send their electronic return to IRS, they should check with their transmitter for specific information. When the transmission to IRS is successful, the IRS immediately notifies the transmitter that the transmission was received and the return(s) is/are ready to begin processing. Once the transmission file is received, the MeF system validates the returns in the transmission file and creates an acknowledgement file within 24 hours for each one. If the electronic return passed MeF validation, an accepted acknowledgment file is generated. If the electronic return failed MeF validation, a reject acknowledgement file is generated and contains: Error Category - Errors are grouped into a small number of categories Error Message - Rule text or XML validator message Rule Number - Each rule is identified by a unique rule number Severity - 'Reject And Stop' or 'Reject' or 'Alert' (An alert does not cause the return to reject. Information is being provided in the alert to the taxpayer about a condition in that return; however, the return does not reject because of that condition.) Data value - Data value causing the violation (when appropriate)