PGP desktop unexpectedly started intercepting outgoing email
Does anyone have any idea why PGP desktop would have unexpectedly started intercepting my outgoing emails?
I use Mozilla Thunderbird (a version from a couple of years ago) to send mail and have PGP Desktop 10.2.0 installed on my Windows 7 computer (for its encrypted virtual disk feature). I do not use PGP in connection with email, but a couple of days ago my outgoing emails suddenly started being routed via PGP uniiversal service (which reports "sent unsecured. Service disabled by user") I have not updated Thunderbird or PGP in a long time. (The routing via PGP started when another family member was sending an email, and it's possible she accidentally did something that changed things, but that seems unlikely to me.) PGP is consistently intercepting all outgoing Thunderbird emails now, and so far as I can tell it has not done so before.for emails sent using Thunderbird.
I can probably find a way to turn this off (e.g. by turning off the messaging part of PGP desktop), but I'm puzzled by the mystery and would like to understand what happened. I've looked at various things with no luck. Any ideas will be appreciated.