TT won't let me run 2022 and 2023 at same time. I used TT22 to estimate 2023 taxes. I want to have TT 2022 and 2023 open at the same time to paste answers across files. TT won't let me run (open) 2022 and 2023 at same time and gives me some error that another user has file open.
The programs should be able to run simultaneously on your computer.
Are you starting each program from its respective .exe file (and not the .tax file)?
I have no trouble running 2022 and 2023 TurboTax at the same time. It sounds like you might be trying to open the same tax return in both 2022 and 2023 TurboTax. You have to open the .tax2022 file in 2022 TurboTax and the .tax2023 file in 2023 TurboTax.
Don't try to open the tax returns by clicking on the file. Start TurboTax for the appropriate year and open the file from within TurboTax.
If you need more help, tell us whether you are running TurboTax in Windows or on a Mac. Also tell us the exact complete error message that you get, word for word.