Solved! But I don't know how: Quicken was asking me for my bank's registration code every time I ran One Step Update
Quicken was asking me for my bank's registration code every time I ran One Step Update. And I discvered it was a spurious window, because I could cancel out of the window and it proceed with the One Step Update.
But then if I initiate a new One Step Update, it would come back.
I thought I fixed it by clearing cache and cookies in Chrome, but it came back.
So then I uninstalled and reinstalled Quicken. That fixed it but it came back
Then it offered the latest update which I took, but it still failed after the latest update
Then I rebooted again.
Now it's working. I have no idea why.