Two GST portal changes rolled out together in 2025 and are still catching businesses out a year later. Search interest for "GSTR-3B not editable" and "GST return time barred" doubled after each quarter-end. Here is what changed and how to work with it.
Rule 1: GSTR-3B liability is locked from GSTR-1
From the July 2025 tax period (filed in August 2025), the outward-supply tax figures in Table 3 of GSTR-3B are auto-populated from GSTR-1/IFF and cannot be edited. Previously you could type any number in 3B; the portal merely flagged a mismatch.
Why: thousands of taxpayers reported higher sales in GSTR-1 (so buyers got ITC) and lower tax in 3B. Locking closes that gap.
What to do if GSTR-1 was wrong:
- Use GSTR-1A — the amendment window that opens after you file GSTR-1 and stays open until you file 3B for the same period. Add missed invoices, correct values, or amend earlier periods there. The corrected figures then flow into 3B.
- For errors discovered after filing 3B, amend in the next period's GSTR-1 (Table 9/10) as before. The tax difference reflects in that later 3B.
- Credit and debit notes remain the right way to change values on issued invoices — generate them with the credit note tool and report them in GSTR-1.
ITC is still editable. Table 4 (input tax credit) continues to be auto-drafted from GSTR-2B but can be adjusted, subject to the IMS rules explained in our IMS guide.
Rule 2: Returns cannot be filed after three years
Under Section 37/39/44/52 amendments effective 1 July 2025, the portal blocks filing of any GSTR-1, 3B, 4, 5, 6, 7, 8 or 9 once three years have passed from its due date. In July 2025 this meant returns for periods up to June 2022 were permanently barred; every month, another period drops off.
Consequences of a barred return:
- The liability does not disappear. The department can still assess it under Section 73/74 with interest and penalty.
- Buyers who claimed ITC on your unfiled invoices face reversal.
- Your registration is likely already suspended or cancelled for non-filing.
If you have old unfiled returns: file everything that is still within the window immediately, oldest first. Late fee is capped (₹500 per return for nil, ₹2,000 for others under the amnesty caps for older periods, ₹50/day otherwise) but interest at 18% runs on unpaid tax.
A monthly routine that avoids both traps
| When | Do |
|---|---|
| By the 5th | Reconcile sales register with invoices issued; raise credit notes for returns |
| By the 11th | File GSTR-1 (monthly) — this now is your 3B liability |
| 12th–19th | Check GSTR-1A for any corrections; act on IMS to fix GSTR-2B |
| By the 20th | File GSTR-3B and pay |
| Quarterly | Compare books vs portal for the quarter; investigate any variance above ₹1,000 |
Put every due date in your calendar with the GST filing calendar — it exports an .ics with 3-day reminders.
FAQ
I filed GSTR-1 with a wrong invoice value. Can I fix it in 3B?
No. Amend it in GSTR-1A before filing 3B for that month, or in the next month's GSTR-1. The 3B figure follows GSTR-1.
Is the 3-year bar applied from the original due date or the extended one?
From the due date as notified for that period (including any general extension notified at the time).
Does hard-locking apply to QRMP quarterly filers?
Yes — the quarterly GSTR-3B is auto-populated from the quarter's GSTR-1 and IFF filings and is non-editable in the same way.
Can I still claim ITC for an old period after three years?
ITC is separately time-barred: it must be claimed by 30 November following the financial year of the invoice (or the annual return, whichever is earlier). Old ITC is lost regardless of the return bar.