TL;DR — Quick Summary

Fix RFC mismatch, expired CSD, and invalid XML errors when submitting the Aspel COI trial balance to Mexico's SAT. Step-by-step guide with XSD validation.

When Aspel COI generates the trial balance (balanza de comprobación) XML for submission to Mexico’s SAT, errors can range from a mismatched RFC to an expired CSD certificate or an XML that does not comply with the XSD version 1.3 schema. This article covers the most common errors when generating and submitting the monthly trial balance, including the complete workflow with the chart of accounts, digital signing, and receipt verification on the SAT portal.

The Error

The most frequent error messages when generating or submitting the trial balance from Aspel COI are:

  • “Error al generar XML de la balanza de comprobación” — generic message that may indicate accounts without a SAT grouper code or required empty fields such as month, year, or submission type.
  • “RFC del contribuyente no coincide” — the RFC configured in COI does not correspond to the RFC on the CSD or e.firma used for signing.
  • “Error en la estructura del XML” — required fields are missing: Mes, Anio, TipoEnvio (N/C/X), or the XSD schema namespace is incorrect.
  • “Error al firmar digitalmente el archivo” — the CSD is expired, the .key file is incorrect, or the e.firma (FIEL) is being used instead of the CSD.
  • Accounts with zero balance included in the XML — accounts with no activity appear with zero balance; some SAT validators reject them if they are not in the previously submitted catalog.
  • “El XML no cumple el esquema XSD versión 1.3” — older versions of Aspel COI generate XML with the 1.1 or 1.2 namespace, no longer accepted by SAT.
  • “El catálogo de cuentas no ha sido enviado” — SAT rejects the balance because no chart of accounts is registered for that fiscal year and RFC.

Cause of the Problem

Incorrect RFC or taxpayer data in COI

The trial balance XML includes the taxpayer’s RFC in the RFC attribute of the root element. If in Aspel COI (Empresa > Datos del contribuyente) the RFC has a typo, an extra character, or is missing the homoclave, SAT will reject the file because the RFC in the XML does not match the authenticated RFC on the portal.

Expired CSD or incorrect use of the FIEL

The Certificado de Sello Digital (CSD) has a 4-year validity and is the certificate companies must use to sign electronic accounting files. Common mistakes:

  • The CSD has expired and was not renewed at SAT.
  • The e.firma (FIEL) of the legal representative is being used instead of the company CSD. The FIEL is for personal transactions, not for sealing electronic accounting files.
  • The .cer and .key file pair do not match the same certificate (files from different CSD periods are mixed up).

Accounts not mapped to the SAT grouper catalog

SAT requires every account to be linked to a code from the minimum grouper catalog (Annex 24 of the Resolución Miscelánea Fiscal). Codes range from level 1 (main accounts, e.g. 100) to level 4 (specific sub-accounts, e.g. 102.01). An account without a grouper code is excluded from the XML, resulting in an incomplete trial balance or a structure error.

Chart of accounts not previously submitted to SAT

SAT requires the chart of accounts (CatalogoCuentas XML) to be submitted before the first trial balance of the fiscal year. If this step is skipped or new accounts are added without resubmitting the chart, SAT rejects the balance because it contains accounts not registered in the catalog.

Outdated XSD schema version

Older versions of Aspel COI generated XML with the namespace www.sat.gob.mx/esquemas/ContabilidadE/1_1/BalanzaComprobacion (version 1.1 or 1.2). Since 2017 SAT only accepts version 1.3. If COI is not updated, the generated XML will have the wrong namespace and will fail XSD schema validation.

Step-by-Step Solution

Step 1: Verify RFC and taxpayer data in Aspel COI

  1. In Aspel COI go to Empresa > Datos del contribuyente.
  2. Confirm the RFC is identical to the one on the active CSD (including the homoclave, which is 3 characters for corporations).
  3. Verify the fiscal regime matches the regime under which the company operates with SAT.
  4. Save any corrections and restart Aspel COI so that changes apply to the XML generator.

Step 2: Map all COI accounts to the SAT grouper catalog (levels 1 to 4)

  1. Go to Catálogos > Plan de cuentas in Aspel COI.
  2. Enable the Agrupador SAT column in the view if not visible (Ver > Columnas).
  3. Sort by the Agrupador column to quickly identify accounts without an assigned code.
  4. For each account without a grouper: select it, click Modificar, and assign the Annex 24 RMF code for the account type:
    • Current assets: 100 to 109
    • Non-current assets: 110 to 179
    • Short-term liabilities: 200 to 209
    • Equity: 300 to 309
    • Revenue: 400 to 409
    • Costs and expenses: 500 to 599
  5. Assign level-4 grouper codes whenever possible for more specific SAT audit traceability.
  6. Accounts with zero balance that never had transactions can be excluded from the XML by checking “Excluir cuentas sin movimiento” when generating the trial balance.

Step 3: Generate and submit the chart of accounts XML to SAT

  1. Go to Reportes > Contabilidad electrónica > Catálogo de cuentas.
  2. Select the corresponding fiscal year.
  3. Click Generar XML. COI will create the file CatalogoCuentas_RFC_AAAA_MMMM.xml.
  4. Sign the file with the active CSD of the company (not the FIEL).
  5. Log in to the SAT Portal with e.firma, go to Contabilidad Electrónica > Envío de información contable.
  6. Select Catálogo de cuentas, upload the signed XML and submit.
  7. Download the receipt and save it before proceeding with the trial balance.

The chart of accounts needs to be submitted once per fiscal year, or whenever new accounts are added. It does not need to be resubmitted monthly if the chart has not changed.

Step 4: Generate the trial balance XML with the correct submission type

  1. Go to Reportes > Contabilidad electrónica > Balanza de comprobación.
  2. Select the month and year of the reporting period.
  3. Choose the submission type:
    • N (Normal): first submission for that month/year.
    • C (Complementary): correction to a normal balance already submitted.
    • X (Complementary correction): correction to a complementary balance.
  4. Click Generar XML and save the file.
  5. Verify the XML contains the namespace www.sat.gob.mx/esquemas/ContabilidadE/1_3/BalanzaComprobacion. If it shows version 1.1 or 1.2, update Aspel COI before continuing.

Step 5: Validate the XML against XSD schema version 1.3

  1. Download the electronic accounting validator from sat.gob.mx.
  2. Open the validator and load the trial balance XML.
  3. Run the validation. The most common errors are:
    • Mes or Anio field empty or out of range — correct in Aspel COI.
    • Invalid TipoEnvio — verify it is N, C, or X (uppercase).
    • Account not included in the catalog — resubmit the updated catalog.
    • Balance with more than 2 decimal places — update Aspel COI so the XML rounds correctly.
  4. Fix all reported errors and regenerate the XML until validation succeeds.

Step 6: Sign with valid CSD and submit to SAT

  1. In Aspel COI, when generating the balance XML, select the Sign with CSD option.
  2. Select the company’s CSD .cer file and the corresponding .key file.
  3. Enter the CSD password (not the e.firma password — they are different).
  4. COI will generate the digitally signed XML file.
  5. Log in to the SAT Portal, go to Contabilidad Electrónica > Envío de información contable.
  6. Select Balanza de comprobación, upload the signed XML, select the month/year and submit.
  7. Download the receipt with the assigned folio and save it as evidence.

Alternative Solution

Validation and submission via SAT Buzón Tributario

If the main electronic accounting portal has technical issues or you prefer an alternative route:

  1. Log in to the SAT Buzón Tributario (buzon.sat.gob.mx) with your e.firma.
  2. Locate the Contabilidad Electrónica section inside the Buzón.
  3. Upload the trial balance XML already signed with the CSD.
  4. The Buzón Tributario accepts the same XML files as the electronic accounting portal and generates an equivalent receipt.

Renewing an expired CSD

If the error is due to an expired CSD:

  1. Log in to the SAT portal with your valid e.firma.
  2. Go to CSD > Renovación de sellos digitales.
  3. Generate a new CSD request for the company RFC.
  4. Download the new .cer and .key files and update them in Aspel COI (Empresa > Certificados digitales).
  5. Regenerate and re-sign the trial balance XML with the new CSD.

Prevention

To avoid recurring errors when submitting the trial balance to SAT:

  • Validate the RFC in COI at the start of each fiscal year. A change in company name, registered address, or fiscal regime at SAT can leave the RFC out of sync with COI.
  • Renew the CSD at least 30 days before expiration. The SAT portal sends email notices when the CSD is about to expire; do not ignore them.
  • Never use the FIEL to sign electronic accounting files. The e.firma is for the legal representative’s personal transactions, not for sealing company files. Keep the CSD and e.firma separate and clearly labeled.
  • Submit the chart of accounts whenever a new account is created, before that month’s closing. Do not accumulate new accounts without an updated catalog submission.
  • Update Aspel COI when SAT publishes new XSD schemas. RMF updates can change required XML attributes.
  • Save receipts for both the catalog and the trial balance in a folder organized by fiscal year and month. They are essential during a SAT electronic review.
  • Validate the XML locally before uploading to the SAT portal. The local validator gives clearer error messages than the online portal.

Summary

  • The “RFC does not match” error originates from incorrect data in Empresa > Datos del contribuyente in COI.
  • The trial balance must be signed with the company CSD, not with the personal e.firma (FIEL).
  • Aspel COI must be updated to generate XML with the XSD schema version 1.3 required by SAT.
  • The chart of accounts XML must be submitted first before the first trial balance of the fiscal year, and updated whenever accounts are added.
  • All accounts with transactions must have a grouper code from Annex 24 of the current RMF.
  • Use the local SAT validator before uploading the XML to the portal to detect structure errors.
  • Always save the receipt with the submission folio as evidence for audits.