On two computers, after the 21-22 update, the foreground window below appears; none of its buttons work. The background window below does not close; it continues to show progress. I had to kill UPDATER and TCMD.
Okay, tried again today. Loaded a fresh V20.22 from the website. This installed without any problems. It didn't, however, recognize my key (see attachment, which says, in effect, that my test version has expired). Manually entering my key in the following box had the same result.
Copied back the V20.17 files and everything works in this version.
My first (and very wild) guess is that the verification fails because of the malfunctioning of GlobalSign (the certificate authority) last week.
If that is the case, it will solve itself within a few days (certificate client cache will be refrehed after 4 days)