The note from herbb623tt about Ransomware Protection in Windows 10 Windows Defender anti-virus settings also worked for me.
I had an option to simply add an exception rather than disabling the entire feature … "Add an app through Controlled folder access". I browsed to the location of the TT executable file. I had to exit and restart TurboTax. Before doing this I was able to save my in-progress tax return to a USB drive. After starting TT I was then able to read the return off the flash drive and re-save it to my hard drive.
TT location on my pc: C:\Program Files (x86)\TurboTax\Deluxe 2018
