The Internal Revenue Service (IRS) processes millions of tax returns during the 2026 tax season, but a significant number of taxpayers are experiencing lengthy delays in receiving their tax refunds. The root of the problem lies in numerous errors when completing tax forms, combined with recent changes in tax legislation and reductions in the agency’s workforce.
Statistics reveal specific patterns of reporting errors that disrupt the normal processing flow. The federal agency has identified ten main categories that account for the majority of delayed cases, ranging from numerical discrepancies to omissions of banking information. Let’s take a look at some of the most common filing errors you must avoid.
IRS Tax Filing Errors: Confusion in the Schedule 1-A Form
The new Schedule 1-A attachment represents the most frequent obstacle in 2026. This document allows seniors to claim the $6,000 deduction, but it requires absolute accuracy in calculating Modified Adjusted Gross Income. The IRS’s automated system compares these numbers with Form 1099s filed by employers and financial institutions.
When the values don’t match, the return automatically goes to manual review. This process adds four to six weeks to the standard processing time. People over 65 are the most affected demographic, and many are unaware of the precise methodology for calculating MAGI or make arithmetic errors.
Incorrect Bank Details Trigger Automatic Freezes
Incorrect or incomplete banking information triggers a “soft freeze” in the IRS system. Blank fields now generate Notice CP53E, which requires taxpayers to provide their banking details online. This mandatory procedure adds a six-week delay to the standard timeline.
Routing and account numbers must be transcribed exactly as they appear on personal checks. A single incorrect digit invalidates the entire information and triggers additional verification. Direct deposit significantly speeds up refund processing when set up correctly, while physical checks experience additional delays of two to three weeks.
Form 1099-K Creates Discrepancies Between States and the Federal Level
Confusion over the 1099-K reporting threshold is causing massive processing bottlenecks. Although the federal threshold was reverted to $20,000, many states kept their thresholds at $600. This discrepancy creates mismatches between state and federal data that the IRS must manually reconcile.
Independent contractors and platform sellers receive Form 1099-K from payment processors. These documents report gross income before deducting operating expenses. The lack of uniformity in income thresholds across jurisdictions complicates matters and requires careful attention when completing the income sections.
“Lookback” Provision Extends Verification Times
Using the “lookback” provision forces the IRS system to retrieve old transcripts to verify the numbers. This procedure causes a 10- to 14-day delay in returns claiming the Earned Income Credit or the Child Tax Credit.
The lookback provision allows taxpayers to use higher income from the previous year, potentially increasing the amount of certain credits. However, this flexibility comes at a cost in terms of processing time. Taxpayers who experienced income reductions in 2025 should weigh the financial benefit against the additional weeks of waiting.
The Clean Energy Credits Require Specific Documentation
Seniors who claimed the Residential Clean Energy Credit face new scrutiny. The IRS now requires specific documentation on “Qualifying Product IDs” for solar systems, heat pumps, and other eligible equipment installed on residential properties.
Manufacturers must provide these unique identifiers that certify compliance with energy efficiency standards. The absence of any of this documentation results in automatic disqualification of the credit. The value of these credits can reach tens of thousands of dollars, which motivates the IRS to implement stricter controls.
Mathematical Errors Trigger CP11 Notifications
The Mathematical Error Notification (CP11 Notice) can be triggered by a discrepancy in a dependent’s Social Security number, a typo in the direct deposit routing number, or an entry on the wrong line. These notices inform you of adjustments that affect the refund amount.
Arithmetic errors include incorrect sums, erroneous transfers of numbers between forms, and improper application of percentages. Tax preparation software reduces these errors, but paper returns are more common. Taxpayers have 60 days to dispute adjustments.
Omission of Income Sources Causes Audits That Delay Refunds
Failure to report all sources of income remains a common problem, especially when taxpayers file early or handle their own returns. The IRS receives copies of all W-2 and 1099 forms directly from the issuers.
The automated system compares reported income against these forms. Any unreported income generates a discrepancy letter, which can result in additional taxes, interest, and penalties. Filing early, before January 31, increases the likelihood of unintentional omissions. Experts recommend waiting until mid-February to ensure receipt of all necessary tax documentation.
