Starting in early January, I attempted to update my Quicken version 6.4.5 to 6.5.1 using the prompts when starting the application. The download and update process seemed to go fine, but when it attempted to open my quicken data file, it reported that it could not do so, and only offered me the options of starting from scratch or going back to convert an older version like a 2017 data file, etc. I am on a MacBook Air, retina 2020 laptop with MAC OS 10.15.7 running. The only way I was able to recover from the above problem was to delete the updated version of Quicken from my applications folder, and copy over a 6.4.5 version backup that I had on a backup drive. Having done that, everything works normally and all my data seems fine. I attempted the upgrade today, trying to go to 6.5.3 now, and had exactly the same result. I have screen shots of the error messages I got after the upgrade, when I attempted to open my data file.