If YOU didnt Efile the original with your ProSeries, then you can't Efile the amended with ProSeries.

Its a program limitation.

See Question 3.

https://proconnect.intuit.com/community/proseries-tax-news-updates/discussion/individual-amended-for...

"Can all Individual Amended filing types be e-filed?
Only an e-filed Form 1040 can be amended. An original return that was paper filed cannot have an e-filed amended return. The original return must have been e-file through your ProSeries software."

Thanks for the information.

That limitation kills the point of Efiling amended Form 1040-X as you can Only do it on the Original returns that you filed Not on returns that was Efiled by someone else.

Intuit says they hope to change this in the future, but didn't give any type of ETA.

There is no point in e-filing an amendment if I cannot do it for a client that I did not originally prepare the return. Most of the amendments I have done and I do are for clients that come to me to correct a mistake done by someone else.

Nowadays, with all the delays implied because of the covid related issues, e-file a 1040x is needed as never before, since the paper returns are taking forever to be processed if not lost in the system.