I withdrew the excess amount in time and i ahve reported the gross amount as "Less common income" Following the steps in this ticket https://ttlc.intuit.com/questions/4698683-in-my-elective-deferrals-to-401k-i-have-an-overage-how-do-....
When I try to file my return, Turbotax won't allow me to file because the 401k field is higher than 18500. It keep sending me back asking me to check the field.
What should I do? edit the the W2 401k field? Is there a step i've missed?
No, you should not edit your W2 401(K) field and you haven't missed any steps.
TurboTax is aware of the e-filing issue that you are having and is currently working on a solution. An update to fix the issue is expected to be released around 4/5/2019.
Be sure to sign up for updates to be alerted as soon as there is a solution. If you do not want to wait for an update, you have the option to paper file your tax returns as this is only an e-filing issue.
You can check out this TurboTax FAQ for more information: Excess 401(k) Contribution Preventing E-filing.