I just received a new message in Charles Schwab now (dated 2/26/2025) :
"Your original tax forms for 2024 will be available online by February 28, 2025. You’ll also be able to import your data into tax software at that time. Questions? Visit our Tax Center."
I guess maybe that's the reason why we're not able to import the data now even though we saw the file was already there.
