I had a similar problem. It would import, but it would corrupt the data in the *.tax2023 file.
This worked for me:
Install TurboTax 2023.
Open the 2023 program and let it update. Apparently there were some last-minute bug fixes.
Open the *.tax2023 files in TT2023 and compare the numbers to the saved pdf version or your 2023 W-2s.
Check to make sure the numbers are correct. If the refund/payment amount matches exactly, your data is probably OK. Edit if needed.
Save the *.tax2023 file and close the 2023 program.
Open TT 2024.
Start a new return instead of using an old one. The old 2024 may be corrupted.
Try to import *.tax2023 again.
Note: importing 2023 data is a one-way street. Once it is in 2024 it can't be changed.
