@Ebony A I was able to efile with Form 1116 but am now trying to file an amended return and failing with a different error message on the same form. Several others are too, as you can see on this thread: https://ttlc.intuit.com/community/taxes/discussion/re-can-t-e-file-unable-to-locate-attachment-at-at...
I tried uninstalling and reinstalling as you suggested, but TurboTax ended up stuck trying to force me to pay again for my free state (with TurboTax Deluxe on Windows) so I wasn't able to continue my return. I instead installed on a different Windows machine and was able to download the free state (California) and continue my return, but eFile failed with the same error. [Update: I was able to restore the Program Files directory from a backup to unstick my original computer back to the original state.]
