What I did with this is added the 1099 r so I would be taxed the excess in 2018. I get an e-file error as noted below on the summary w2 sheets only. Just override the numbers so you do not have the over amount. This clears the error. These sheets are just summary sheets and do not get e-filed. The w2 stays the same as originally input with the over contribution which is part of the E-file.

Hmmm...that is interesting. So the error is coming up because of a lousy worksheet? How does the W2 stay the same as originally input with the over contribution???

No.  The error comes up because the W-2 box 12 amount exceeds the deferral limit's.    It is correct for TurboTax to flag that as a error (which it is) to alert the taxpayer to a possible data entry error that they can correct, but it should not prevent e-fileing if there was no data input error and there really is an excess on the W-2.  (The worksheet is just where TurboTax stores the W-2 data.)

(W-2's do not get physically sent to the IRS, just the encrypted data from the W-2 gets transmitted to the IRS and most of that data comes from the worksheet.   The TurboTax W-2 "form" that you fill out in the interview is not a W-2 form, just a TurboTax mock up of the form as a data entry screen. Changing the worksheet will probably also change the data sent to the IRS and most likely will cause a data mismatch between what you file and what the employer filed.  Worksheet themselves are not sent to the IRS, but the data that they contain can be.)

Has it been confirmed TT will be updating to allow for efiling? I am ready to file and don't want to mail in if efiling is an option.  

I don't understand the logic behind this issue, TT knows its an over contribution and the corrective action, why prevent efiling?

TurboTax has released a FAQ on this issue - the answer is to print and mail the return.
Excess 401(k) Contribution Preventing e-File

https://ttlc.intuit.com/replies/7327357

Wow, that's pretty big letdown. Might as well file the taxes by myself then.

What I did with this is added the 1099 r so I would be taxed the excess in 2018. I get an e-file error as noted below on the summary w2 sheets only. Just override the numbers so you do not have the over amount. This clears the error. These sheets are just summary sheets and do not get e-filed. The w2 stays the same as originally input with the over contribution which is part of the E-file.

can someone from turbotax confirm this work-around (nice, btw!) if the program does not get updated to fix this issue as planned by 4/5/2019

How do you override the numbers in the summary w2 sheets only?

I'm using premier Mac version and the override button is grey for summary w2 sheets.

I'm using premier Mac version and the override button is grey for summary w2 sheets.

Turbo tax released a new version which longer always you to do this. You have to wait until; 4/5/19 for fix

I only contributed like $5 over the 2018 401k limit, but my 401k said that it's past their deadline and they can't do anything now. Any advice? It feels stupid just for several bucks (It happened because I switched jobs in 2018).