File Copied and wont e-File

You’re not going to be able to efile  a 2026 return prepped in the 2025 software. The system knows there is already a 2025 return, and 2026 efiling is not open yet.

FYI in case this is relevant to any future searcher - the answer is that you’ll never be able to e-file a copy of a return that’s already been filed. In my case, I had two children with identical investment accounts - but I didn’t know that until after the first kid’s return had been filed. “I’ll just copy the file and update name and SSN and save myself a bunch of input,” I said. Nope. Got to start from scratch once an e-file has been transmitted. A copy works fine prior to that point.

For entity returns, the same problem you have now - only one return accepted per form year - is the case. So if you have a short-year 2026 partnership return that’s due before 2026 forms are out so has to be filed on 2025 forms, you are stuck filing either the 2025 or short-year 2026 on paper.