Using classic Outlook for Windows in business environments
Given the date this problem surfaced, I'm beginning to wonder whether this was a Microsoft employee's idea of an April Fool's joke which they forgot to reset. The issue is definitely on Microsoft's end as - like everyone else affected -the problem started for me a few days ago and I have performed all the reset and clearing options to no avail.
Find out who has a twisted sense of humour, make them restore the old code that they have so obviously buggered about with and then fire them.