I previously used an Outlook add-in that linked my Outlook software to Practice Panther, which was my client management software. When I changed from Practice Panther to another CMS I uninstalled the Practice Panther add-in. Unfortunately, this add-in used autocomplete entries for storage of emails under "contact" and "matters" in Practice Panther, but even after deleting the add-in I cannot get rid of these contact and matter autocomplete entries. This is problematic because when selecting a client to send an email to I end up getting a bunch of autocomplete entries related to Practice Panther rather than the client's email address, and I have to hunt for the right one. So when typing "John Smith" I do not get his email but instead get a Practice Panther contact or matter autocomplete option such as Email address removed or Email address removed.
I have deleted all of my contacts, deleted autocomplete storage, went through each and every contact and matter name individually through Outlook online, searched and deleted all registry keys related to Practice Panther, and nothing I do will remove these autocomplete entries. They repopulate as soon as they are deleted and I cannot figure out where they are stored or how to delete them.
The guys at Practice Panther say they have no idea and told me to speak to Microsoft. After 2 chats with tech support at Microsoft and doing what I was told I still have no solution. Tech support first had me uninstall and reinstall all of my Office apps, and when that did not work I had a tech send me 6 year old article that users in the article were noting was outdated in 2019 so he tried to do it personally by taking over my screen and after 15 minutes I just told him to stop because all he had succeeded in doing was changing the color of my Outlook background.