Environment: Thunderbird Portable 9.0.1 on Windows XP Pro (32 bit).
Thunderbird Portable is run from the local hard drive (not from a USB one).
Thunderbird Portable has been upgraded from earlier versions gradually.
Scenario:
Installed automatically (from TERENA Personal CA) a personal certificate in Firefox Portable 9.0.1. I created certificate backup and imported into Thunderbird Portable (9.0.1), then I enabled in an account signing and encryption using this certificate. The account includes copied mail. Signed messages sent using this account cannot be verified.
THIS PROBLEM DOES NOT OCCUR WITH A FRESH INSTALLATION OF THUNDERBIRD (NOT PORTABLE). It also does not occur with other mail clients (e.g. MS Outlook).
However, using other certificates, like the ones generated here: https://digitalid.verisign.com/client/class1Netscape.htm, we can create verifiable messages. (Edit: This, after subsequent investigation, seems irrelevant. The problem is with the account, not with the certificate.)
Why Thunderbird Portable cannot send a signed mail message which can be verified successfully, when mail folders have been copied (migrated) from elsewhere (another TB installation)? And why this does not happen in Thunderbird (standalone)?
Any advice?
Thanks,
Nick