While it is possible that the Georgia return would not efile for the reason you indicate, the more likely reason is a glitch in TurboTax for the State of Georgia. As you note, returns with Series 100 credits must be efiled in Georgia. As you go through the prompts, TurboTax requires that you attach the Series 100 credits to the return (or you get an error message). However, TurboTax will not allow the filing of a return with an attachment. I used 2018 Home & Business, and had two extended calls with support. At the conclusion of the first call, support (incorrectly) decided that the problem was that I had downloaded H&B for Mac, and should have used the cloud version. But a colleague had the same issue with that version. I did talk to the Georgia Department of Revenue, who intimated that I should use a different software provider for 2019. According to the GDOR, the necessary correction here is for TurboTax to eliminate the requirement of attaching the Series 100 credit because those credits already were submitted (in my case with a K-1), and either not required or (if required) could be submitted later.
