There's some residual settings till present that are interfering with with a second install (following an uninstall, restart, new/second install). So I'm thinking just uninstalling Office 365 and Teams Machine-Wide Installer in Programs and Features isn't good enough. No problems on a 'pure' Windows 10 machine though. No sign of Teams at all, even after restarting a couple times and signing in. In all cases, Teams Machine-Wide Installer never showed up. For the errors a couple times Office 365 installed normally, but sometimes it just didn't install.

Testing on a 'pure' machine worked as expected. Testing was useless on that machine however. I assumed uninstalling it would make it like Office 365 was not there, enough to test some deployment options. But if I uninstall and then reinstall that doesn't always work. I noticed recently that an install on a 'pure' Windows 10 machine that's never had Office 365 works fine, like normal. I'm using the office deployment method for Office 365, including Teams. Why? What's left over from the original install, and how can I remove that?

If I uninstall Office 365 on a test machine and then reinstall it, not everything reinstalls.

Cross posted on r/office365 and r/MicrosoftTeams but no one replied.

Office 365 uninstall tool