Thank you very much for your replies. My computer froze just as I finished a response last night, wiping it out. My computer has crashed a few times lately - I don't know if somehow this could be related to the change in behavior of PGP.
And enough other things have come up for me to deal with that it seems I don't have much time to
follow up on this right now.
The only PGP log I've found is the PGP desktop log. When PGP desktop starts up the log reports:
*A 10:38:34 ----- PGP Desktop started -----
*A 10:38:34 PGP Desktop 10.2.0 (Build 1672) (1672)
*A 10:38:34 Today's date is Saturday, July 26, 2014
IP 10:38:37 Setting logging level to: normal
IE 10:38:38 Email proxying is enabled and active
This does not seem to have changed.
Before the behavior change, sent emails were not mentioned in the PGP log in the cases I've looked at.
After the change in behavior, I see in the log, for example:
WE 16:21:11 Server nb-smtpauth-vip2.prodigy.net presented a TLS certificate for a domain name which does not match (NLPI162.PRODIGY.NET)
IE 16:21:25 Processing outgoing message from XXXXXX <xxx@xxxx.com> with subject: Monday Aug 4
WE 16:21:25 Sending message unsecured
If I look at an email that I sent to myself, after the change, the header lines include two mentions of PGP Universal, for example header lines like the following:
Received: from [127.0.0.1]
by echo (PGP Universal service);
Fri, 01 Aug 2014 11:50:00 -0800
X-PGP-Universal: processed;
by echo on Fri, 01 Aug 2014 11:50:00 -0800
(echo is the name of my computer.)
Neither of these lines appeared before the change.
When I compare old backup versions of the PGPpolicy and PGPprefs files and the Thunderbird prefs file with current versions, I don't spot any changes that to my eye look like they would account for the change in behavior.
What might have changed that could have changed whether or not PGP intercepts the emails - something I'm not seeing in the PGP or Thunderbird AppData files, or something somewhere else?
Any further thoughts will be appreciated.