https://ttlc.intuit.com/questions/3206604-error-code-65535-unexpected-error
I get the same error message when I tried to install TT 2020. I did send the error report to Intuit. I wonder if Windows 10 caused it! 🙂
here's a link to what Microsoft suggests. Don't know if it's any better.
https://answers.microsoft.com/en-us/protect/forum/protect_defender-protect_scanning-windows_10/file-system-error-65535/0208a71b-58a1-488d-8a73-95a3b3316727#:~:text=%20File%20system%20error%20%2865535%29.%20%201%20Click,5%20Tap%20or%20click%20Startup%20Settings.%20More%20