Thanks, but don't think those suggestions address the issue. Users will mostly just click the default when signing in, and that is to cache credentials, so we need a way to stop that from happening. MFA isn't going to work infor various reasons.
The users shouldn't need to sign into anything else - the machines currently have Office 2013, this will probably be upgraded to 2019 (minus Outlook), but there shouldn't be any need to sign into this - the files to be opened will all be on a network share or copied from a USB stick. Teams will only be needed for vocie and video calls.
The machines aren't domain joined so GPOs won't be possible either. I guess what I'm asking is whether there is a registry key or similar method which prevents Teams from caching credentials.
Thanks