TT customer service directed me to the following web page where I could download all the TT updates at once, as a separate executable file: https://ttlc.intuit.com/turbotax-support/en-us/help-article/update-products/manually-update-turbotax...
This solved my issue that TT would provide an error when I was trying to open TT, as the updates would fail to install. The separate executable file worked perfectly.
In addition, the TT customer rep advised me to save my personal TT file to my computer, even though TT had been saving it to OneDrive (some sort of default I guess). That addressed the other problem I was having when TT said it could not find my tax return. I moved my file to my PC, and have not had another similar error.
