1040X

There are numerous posts on this issue.

Unless YOU efiled the original return, using PS software, YOU can't efile the 1040-X.

It's an Intuit rule.  One I think is rather stupid.  

(Disclaimer - Bob, I'm not saying Intuit is stupid.)

I have had that problem; I think if you did not efile the original return, you are not able to efile an amended. I have been able to amend returns I efiled, but have never been able to efile an amended return that someone else efiled. which doesn't make sense, only time I amend a return I prepared is if my client forgot something or got a K-1 2-4 months late!

You need to separate "Efile" and "amend" and "who prepared" it. You have it all confused.

For 1040X:

Intuit provides the Program you are using. This program is only set to Amend a return that you prepared in the program, and it will only Efile that amendment if the original return You Efiled, from This Program, also was Efiled.

Of course you can amend any return, even if you did not prepare the original. You can paper file anything.

You cannot Efile that amendment, even if it was Efiled originally (but by a different program and/or by someone else), or even if it was paper filed by anyone (including you), unless it was Efiled by You, using the same program now (to amend) that you used originally, to prepare and Efile the original return you are amending and would like to Efile.

It has nothing to do with the IRS or anything other than, the way your Program was programmed.