Can I not e-file an amended return?

[gmhorner]

I got an amended W2C form from my employer with a lower annual salary for 2016.

[AndreaC1]

Amended returns have to be printed and mailed. They can't be e-filed per IRS regulation. It is recommended to wait until the IRS has accepted your initial return and you have received your federal refund before you amend the return. And the filing instructions page that prints with the return will tell you what needs to be included. If you have done the amend steps and you need to get back in and print the return, the steps to do so can be found below. 

If you have not done the correct amend steps, the instructions can be found here https://ttlc.intuit.com/questions/3402261

Detailed Instructions for TurboTax Online:

1. Log in to your account.
2. Click on Amend (change) return.
3. Click on the Amend using TurboTax Online button.
4. Select the My Account drop down in the upper right and choose Print Center.
5. Under the Choose your option: section, select which forms you want to print.
6. Click Print save or preview this year’s return.
7. Click View or Print.
8. Mail to the address specified in your return.

NOTE: If you are using Desktop version, go here for steps https://ttlc.intuit.com/questions/3218365

And you can find a list of frequently asked questions, about amended returns, here Form 1040X, Amended U.S. individual Income Tax Return, Frequently Asked Questions  

https://ttlc.intuit.com/replies/4173080