I am stuck unable to file because New York State is asking for an amount for IRC 125 / Code A-101 - I have no such figure on my W-2

It sounds like you're encountering an issue with TurboTax related to the New York City flexible benefits program (IRC 125), typically reported under Code A-101 on your W-2. 

Here are some steps to resolve this and how to get back to your W-2 to correct it:

1. Return to the W-2 Section: Use the search bar (magnifying glass at top right of screen) to type "W-2" and select the "Jump to" link.
2. Check Box 14 on your W-2: Ensure that Box 14 doesn't have any entries related to IRC 125 or flexible benefits. Sometimes, it might be labeled differently
3. Clear any zero entries: If you entered a zero for this amount on your W-2, try deleting the zero and leaving the field blank
4. Delete and Re-enter the W-2 Manually: If the error does not clear, try deleting the W-2 by clicking the delete/trash icon next to the W-2 entry, and then re-enter the information manually
5. Request a Corrected W-2: If you should have an IRC 125 amount* and your employer left it out of Box 14, reach out to your employer for a corrected W-2

* IRC 125 Requirements:

• If you made 414(h) retirement contributions to a public employee retirement system, report these as an addition to your federal AGI on your New York State income tax return (line 21 on Form IT-201 or IT-203).
• For the New York City flexible benefits program (IRC 125), report the deducted or deferred amount as an addition to your federal AGI on line 23 of Form IT-201 or line 22 of Form IT-203.
• Both amounts are found in Box 14 of your W-2.

For more information on IRC 125 requirements, you can visit the New York State Department of Taxation and Finance and NYC.gov