I find there is much confusion around this topic, so I’ll try to clear it up here. First off, non-imported profiles are well… not imported. They were not created by Profile Sync / AD Import / Sync with External Identity Manager. We also refer to these as “unmanaged”, or “stub” profiles because they typically only

Update: There was a fix for this behavior in the SharePoint 2016 August 2020 Public Update (build 16.0.5044.1001), so if you’re past that build and seeing the “batch abort exception”, it’s more likely that it indicates a real problem.   Here’s an example of an error that often occurs during Active Directory Import (aka: ADI,