SUA IMSS: Bimonthly Quota Calculation Error Fix

TL;DR — Quick Summary

Fix SUA IMSS bimonthly quota errors: load EMA, import IDSE, correct insured days and disabilities before generating the SIPARE payment file for the bimestre.

Diagrama

The bimonthly quota calculation error in IMSS SUA is one of the most common blockers for Mexican payroll teams at each bimestre close. Unlike a single-worker issue, this failure usually means SUA cannot integrate the data sources that feed worker-employer quota calculation: quota tables, Monthly Advance Issuance (EMA), IDSE movements, effective insured days, and disabilities. When the process stops, you cannot generate the SIPARE payment file, exposing the employer to late-payment surcharges.

This guide covers common causes, diagnostics in SUA, and step-by-step recovery before paying IMSS quotas.

The Error

When running Determination of quotas > Calculation for a bimestre, SUA may show:

“Error calculating bimonthly worker-employer quotas”

“Monthly Advance Issuance not found for the period”

“Worker insured days do not match the selected bimestre”

“Error reading quota table. Verify SUA version”

Sometimes the calculation finishes without an error message, but the SIPARE file shows significant differences from what the IMSS portal expects — equally dangerous because rejections or discrepancies may appear weeks later.

Root Causes

SUA combines four data layers for each active worker in the bimestre:

Affiliation movements imported from IDSE (hires, terminations, salary changes, rehires).
Contribution Base Salary (SBC) within the 25-UMA cap.
Net insured days, minus disabilities and absences.
Quota tables and EMA published by IMSS for the current fiscal year.

Missing or outdated EMA

EMA contains IMSS-estimated quotas for the first month of the bimestre. SUA uses EMA as the starting point for the second month. Without EMA, or with the wrong month loaded, bimonthly totals diverge from SIPARE.

Pending or rejected IDSE movements

Movements must flow from IDSE to SUA via the response file (.txt). If HR updated the IMSS web portal but never imported the receipt into SUA, local data is stale. Rejected movements — wrong NSS, late dates, inconsistent SDI — also block calculation.

Incorrect insured days

Each worker needs exact insured days for the bimestre, accounting for hire/termination dates, IMSS disability folios, suspensions, and rehires. A worker with 61 insured days in a 60-day bimestre, or zero days while active, triggers validation errors.

Outdated quota tables or SUA version

IMSS publishes periodic SUA updates with new quota tables and integration factors. Running an old version — especially at the start of a new fiscal year — causes table read errors or wrong rates.

For 2026, verify daily UMA ($113.14) and the contribution cap (25 × UMA = $2,828.50 daily).

Unregistered disabilities

Disabilities reduce insured days and may change calculation bases. If IMSS has a disability SUA lacks — or vice versa — bimonthly totals diverge from SIPARE.

Step-by-Step Fix

1. Verify SUA version and quota tables

Check Help > About for the latest version from imss.gob.mx. Update before recalculating. Confirm integration factor and benefits in Configuration > Employer data.

2. Load EMA for the first bimestre month

Download EMA from the IMSS portal. In SUA: Utilities > Load EMA, select the file, confirm EMA loaded status. If calculation still fails, remove and reload with the latest portal file.

3. Import and validate IDSE movements

Download the IDSE response for all bimestre movements. In SUA: Utilities > Import affiliation movements. Review the report — all movements must be Accepted. Fix Rejected items in IDSE and re-import.

4. Audit insured days and disabilities

Run Affiliation > Insured days by worker for the bimestre. Register missing disabilities, fix hire/termination dates, and verify SBC does not exceed the 25-UMA cap.

5. Recalculate and validate in SIPARE

Run Determination of quotas > Calculation, review the error report, generate the SIPARE .SUA file, and validate on the IMSS portal before bank payment.

Prevention

Schedule EMA load, IDSE import, and bimonthly calculation at least 5 business days before the payment deadline.
Back up SUA.MDB before each bimestre close.
Import IDSE movements weekly, not only at bimestre end.
Train staff on legal deadlines (5 business days for hires and terminations).

Summary

Bimonthly calculation errors usually stem from missing EMA, unimported IDSE movements, wrong insured days, or outdated quota tables.
Load EMA, import accepted IDSE movements, and register disabilities before calculating.
Always validate the SIPARE file on the IMSS portal before bank payment.

Guide & Instructions

Estimated Time: 50m

Tools Needed:

SUA
IDSE
SIPARE

Confirm bimestre and current quota tables

Open SUA and verify in Configuration that program version and quota tables match the current fiscal year. Select the exact bimestre you are closing.

Load or update the Monthly Advance Issuance (EMA)

Download EMA from the IMSS portal for the first month of the bimestre. In SUA go to Utilities > Load EMA, select the file, and confirm loaded status before calculating.

Import IDSE movements for the bimestre

Download the IDSE response receipt in .txt format. Use Utilities > Import affiliation movements, load the file, and verify all movements show Accepted status.

Register disabilities and validate insured days

Capture each disability in Affiliation > Disabilities with exact folio, dates, and days. Review the insured-days report and fix inconsistent SBC or work periods.

Run bimonthly calculation and validate in SIPARE

Go to Determination of quotas > Calculation, run the process, review the error report, generate the SIPARE file, and validate amounts on the IMSS portal before payment.

Frequently Asked Questions

Why does SUA fail to calculate bimonthly quotas?

Bimonthly calculation integrates current quota tables, the Monthly Advance Issuance (EMA), insured days per worker, registered disabilities, and imported IDSE movements. A failure in any source stops the process or produces wrong amounts.

What is EMA and why does it affect bimonthly calculation?

EMA is the monthly file IMSS publishes with estimated quotas for the first month of the bimestre. SUA uses it as the base for the second month; if EMA is missing or outdated, totals will not match SIPARE.

How do I verify insured days before calculating?

In Affiliation > Worker inquiry, review insured days for the bimestre. Subtract disabilities, unjustified absences, and periods without active registration. Each out-of-range day causes differences in health, RCV, and Infonavit branches.

Can I recalculate after fixing data?

Yes. Correct data in SUA, rerun Determination of quotas > Calculation for the same bimestre, and generate a new SIPARE file. Do this before bank payment; if already paid, you must file a clarification with IMSS.