EFILE error codes: a rejected T1 isn't filed until EFILE accepts it

How are EFILE error codes grouped?

The official T1 list is Chapter 2 of RC4018, the Electronic Filers Manual, which covers error messages for the 2018 to 2025 tax years canada.ca. The CRA validates a return in stages, and a record has to pass one stage before the next one runs. The code number tells you which stage stopped it canada.ca.

Because the stages run in order, one return can be rejected more than once, with a different code each time canada.ca. Clearing a code 40 doesn't mean the return is clean: it only lets the balancing and error detection checks run. Code 8 means EFILE found more than eight errors and is showing you only eight canada.ca.

Which T1 codes come up most, and what fixes them?

These are codes from RC4018 Chapter 2 that apply to every year from 2018 to 2025 unless the row says otherwise canada.ca. Your software shows the full CRA text for each one.

Codes 370 and 2197 sit in the error detection ranges, so they only appear once the identity checks have passed. A client who overcontributed to an RRSP has a separate problem; see the RRSP overcontribution page.

Why does a name or date of birth mismatch block the whole return?

Codes 40 and 43 compare your entry with what the CRA has on file for that SIN canada.ca. A typo is the usual cause, so confirm the date and spelling with your client and recheck the SIN at the same time, as the manual suggests. If your entry is right and the CRA record is wrong, code 40 can't be cleared from your side: your client has to contact the CRA with original or certified documents before EFILE will accept the return canada.ca.

For a name change, code 43 accepts a new surname when you set surname change code 2, but the first and last name can't both change on the same transmission canada.ca. Code 71 fires if the surname change code itself is missing: use 1 for no change and 2 for a change or a first time filer canada.ca. Code 63 is a date of birth that's in the wrong format, falls less than 10 years before the marital status date, or comes after the date of death canada.ca.

On a return for a deceased client, code 36 means the date of death is before the tax year, and code 38 means the date doesn't match CRA records; check it against the proof of death canada.ca.

Which codes mean the return has to go on paper?

Several codes tell you to file on paper if your entries are correct: 2 (temporary SIN or one starting with zero), 6 (system constraints), 34 (a return for the period before bankruptcy with an immigration or emigration date), 36 (date of death before the tax year), 96 (SFD limits exceeded), 98 (too many livestock or crop inventory entries), 371 (income slip amounts) and 441 (commission income higher than employment income) canada.ca. Code 93 requires paper for 2023 to 2025 when a flipped property shows a net loss, and code 2130 can require paper for 2023 to 2025 when the CRA's immigration or emigration date doesn't match the return canada.ca.

Some returns can't use EFILE at all, so they never reach a code. RC4018 Chapter 1 excludes, among others: a taxpayer who died before the current tax year, returns during and after bankruptcy, non residents unless filing under section 116, emigrants filing Form T1243, T1244 or T1161, returns with NR4 or T4A-NR income, and a return filed with Form RC199 or a Voluntary Disclosures Program request canada.ca. EFILE also only takes the current year and seven prior years, which for the 2026 season means 2018 to 2025 canada.ca. Elections, designations, agreements and waivers must still be sent on paper by their due date canada.ca.

What does a rejection do to the filing deadline?

A rejected return hasn't been filed. Under subsection 150.1(3), an electronically filed return is deemed filed on the day the Minister acknowledges acceptance of it laws-lois.justice.gc.ca, and RC4018 says a confirmation number must be generated by EFILE for the record to count as a return in prescribed form canada.ca. A transmission on April 30 that comes back with code 40 leaves your client unfiled.

Worked example: your client owes $3,000 on the 2025 return, due April 30, 2026. EFILE rejects it that evening with code 40, the CRA's date of birth record is wrong, and the corrected return is accepted on June 12, 2026. That is one full month late, so the penalty is 5% + 1% = 6% of the balance owing, or $180 canada.ca. Had the code been a typo fixed and retransmitted before midnight, the penalty would be $0.

A client with a refund or no balance owing pays no late filing penalty, because the penalty is a percentage of the balance owing, but benefit and credit payments can be delayed canada.ca. If the rejection came from a CRA processing error, ask for relief: the CRA lists errors in processing among the actions that can justify cancelling penalties and interest canada.ca. Deadlines are on our T1 filing deadline page.

How do you retransmit, and who do you call?

Once the errors are fixed you can retransmit, and the document control number stays the same unless code 78 or 81 was on the rejection canada.ca. Code 79 means the DCN has hit its maximum number of attempts canada.ca. A rejected transmission stays listed under View T1 EFILE Service Transmission History until the CRA processes a paper return for it or receives the return from another electronic filer or through NETFILE canada.ca. Since February 2026, a return sent from software other than the one linked to your EFILE account fails canada.ca. The T1 EFILE and ReFILE window for this season runs to January 29, 2027 canada.ca.

For error messages you can't resolve, call the EFILE Helpdesk that serves your office canada.ca. Format errors your software created go to the software developer canada.ca.

Which centre handles T1 error messages depends on your office, and the CRA's page has the chart canada.ca. Questions about Auto-fill my return go to the individual income tax enquiries line, not the EFILE Helpdesk canada.ca.