Nearly all HSA contributions are in two places: (1) on the W-2 in box 12 with a code of W, and (2) in the HSA interview on the "Let's enter [name]'s HSA contributions" screen.
The only place that you can edit the code W amount (called the "employer contribution") is on the W-2 screen. You can edit the direct contributions at any time on the "Let's enter [name]'s HSA contributions" screen.
Of course, you should always enter the code W amount as it appears on your W-2. If there is an error on your W-2, you need to go back to your company to get a corrected W-2, so that the IRS will receive a copy of the corrected W-2.
If you need to start over again with the HSA section, please delete your HSA information by reading the following:
The safest - although brute force - way to fix this is to do the following in this order:
1. make a copy of your W-2(s) (if you don't have the paper copies)
2. delete your W-2(s) (use the garbage can icon next to the W-2(s) on the Income screen
*** Desktop***
3. go to View (at the top), choose Forms, and select the desired form. Note the Delete Form button at the bottom of the screen.
*** Online ***
3. go to Tax Tools (on the left), and navigate to Tools->Delete a form
4. delete form(s) 1099-SA (if one), 8889-T, and 8889-S (if one)
5. go back and re-add your W-2(s), preferably adding them manually
6. go back and redo the entire HSA interview.
