Hi Bob,
No problem, you're welcome. You're friend may be right since your other browsers aren't suffering from the Certificate errors. I haven't used Eudora for years and years. It was a good E-mail program for it's day--sort of Netscape-ish; also a very good program.
If you're using Outlook10 and not getting errors (Outlook 2010 right?),
just remember to back up your PST file, especially with a large address book. Before I ran out of money for the Outlook renewal (after Outlook 2007), I had around 4,500 contacts in my Address book. 20 years worth of contacts and E-mail. File got quite large. As long as you do regular backups; probably 3-4 times a year you should be Ok. I don't know if the Eudora version you were using downloaded E-mail & Contacts to your local hard drive, but the older versions did so too, so I'm guessing you know this fact already. Just in case you don't it's a good idea to let people know.
The industry has changed over the last decade and I've move about 98% of my Customers off from Client-based E-mail programs such as Outlook, Outlook Express, Windows Mail, Windows Live Mail, etc. due to this very backup issue. I now live in a mountain resort town, and most of the folks up here are "low-tech", and they do a very poor job of backing up their computers, and even when a few of them do so, they don't have the technical expertise to know how to backup up PST E-mail files. Many still backup their Quicken onto floppies!! I offer to come to their homes and backup their E-mail for free, and 99% will not let me do that.
In 2009 or so I moved to Windows Live Mail (WLM2011), and have been using that since as a free replacement for Outlook. It works pretty good, though the new Win10 Mail replacement program does not yet work, so I'll have to stay on it for a while longer until MS fixes their bug.
Good luck with your Outlook--it's a really good program for managing large address books; though the E-mail is full-featured, it's still clumsy to work with especially if your E-mail servers are using IMAP/IMAP4.
<<<BBJ>>>