I was having the same problem using the TurboTax 2019 that I just loaded last night on a new laptop running Windows 10. (Like you, I did NOT want to switch, but had not choice, since TT no longer uploads my investment info while running Windows 7 - grrr.)
I inactivated the pre-loaded McAfee real-time protection and firewall and restarted the computer and reopening TurboTax. This time, everything ran fine. My other antivirus program still has all protection settings on, so it was the McAfee that was hanging up TT.
