You need to download the 2023 tax data file ending in .tax2023 to open in the Desktop program.
How to finish a return you started online,
https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-finish-a-prior-year-return-that-i-...
Then for 2024 you can transfer 2023 from your computer into Online or a desktop program. But you have to file 2024 from Online by tomorrow Oct 15. Or you will have to use the 2024 Desktop program after Oct 15. I would try to do 2024 first so you can efile it today or tomorrow from Online. To efile you will need to enter 0 for the 2023 AGI since you are filing 2023 late.
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