Get your taxes done using TurboTax

Yes, sometimes if you make a change in the interview mode, the code will stick, making it hard to remove. When that happens, you need to delete the 8889 and then enter the HSA information back into the return.

1. Go to Forms Mode (top right) of your return. 
2. Find Form 8889-T (and 8889-S for your spouse).
3. Click the Delete Form button ‌ of each.
4. This will reset the "Smart Worksheet." 

Go back to Step-by-Step and re-enter the HSA section. To prevent the "double-checking" of boxes:

1. When asked "Did you have the same coverage all year?", you must answer No.
2. Even though you had the same coverage for 11 months, answering "Yes" is what triggers those top boxes that are currently conflicting with your December status.
3. Enter your coverage for each month manually. This forces TurboTax to only use the 12-month grid and leave the "same coverage" section blank.

Once you've finished the interview, switch back to Forms Mode and verify:

1. Part A (Top): The "Self" and "Family" boxes should be empty.
2. Part A (Monthly): Only Jan through Nov should be checked. Dec should be "None".
3. Line 3: This should show the prorated amount (e.g., $3,942 for 2025 Self-only coverage if Jan–Nov were covered)

You can also do this in the forms mode since forms 8889-T and 8889-S are editable. If you do this, make sure that you do not pick self or family in part A of the smart worksheet. Then check each month individually and then select self-only or family in each of those months. If it is done correctly, it will show $3,942 as the correct pro-rated total under the maximum amount contribution.

@bgix