Solved … but not quite sure how.
Hi Michael. Wow, fast response by you - thanks!
I did check in Mail preferences for the plug-in … everything seemed OK. However, I did see another plug-in from Druide Informatique (Antidote 10 Spell checker French and English - integrated with Mail and with Outlook). I unchecked both the SS plug-in and the Antidote plug-in and closed Mail.
Since Antidote was giving me problems with Outlook (their Connectix service wasn’t functioning) and with Mail, I decided to uninstall it with AppCleaner. I also uninstalled SS.
I shut down the Mac Pro, then restarted it. I installed SS, made sure that it had Full access in Privacy-Protection, opened Mail, rechecked the SS plug-in, closed Mail. Shut down the MP.
Restarted the MP, checked Mail and the Spam Sieve commands were now present! Finished the setup and decided not to transfer the training data after all. SS seems to be running fine now (still working on Antidote). Just in case you were wondering why I am using 2 mail clients … Outlook is used at the request of a client who has given me an email account with them - I have access this way to the company directory etc.). I am wondering if one of the problems with SS was that I installed Antidote first, followed by SS? I really don’t know.
Home folder is still on the Mojave boot drive, for now. Thanks for letting me know about the account naming not being a problem.
Best,
Stu.