Every time you make changes to your return, TurboTax Desktop creates a backup file (.tt25). When you try to save changes you've made, it asks you whether you want to save them. 

To save a PDF file for your records, please follow the instructions below:

Here's how to save a PDF copy in TurboTax Desktop:

Select Review, then Print personal return or forms.

On the Save a copy of your return for your records screen, choose what information you'd like to save or print.

Select Save PDF Copy for Your Records.

This copy is for your records only. Don't mail it to the CRA.

How do I save a PDF copy of my tax return in Desktop?

Thank you for choosing TurboTax.

I've completed part of my return but now want to save what i have done so far and sign out until tomorrow.  How do i do this?

You can go to the top left and click on FILE and click on SAVE.

Thank you for choosing TurboTax.

I've  gone to the top left and clicked on file and entered my file name and then tried saving my tax file multiple times and TURBOTAX 2025 refuses to save my file.   Why is this happening?   What do I have to do to save my tax file?   I've used TURBOTAX for approximately 20 years, and never had this problem before.   

Did you click on "save" or "save as"? Which one was giving you the issue on not being able to save your file?