I’m preparing for a Microsoft 365 tenant consolidation and have been looking into what should be checked before moving Teams data. At first, I assumed the process mainly involved recreating Teams and moving the associated files, but there seem to be several dependencies that can easily be overlooked.

One of the first things I’d recommend is creating a complete inventory. For every Team, it makes sense to record the owner, members, number of channels, private or shared channels, important files, conversations, apps, tabs, and special permissions. Having this information beforehand should make it easier to identify what actually needs to be transferred and what can be left behind.

User mapping also seems especially important. If users are moving from an old organization to a new tenant, their source accounts need to be associated with the correct destination accounts. A mistake here could result in users not having the expected access to Teams, channels, or migrated content.

Another issue is that Teams files are closely connected to SharePoint, while some chat files rely on OneDrive. That means a Teams project cannot always be treated as an isolated workload. SharePoint sites, document libraries, and OneDrive content may need to be included in the overall migration plan.

I’ve also been researching Migrate Teams from One Tenant to Another options and found that the manual route can involve recreating Teams and channels, moving files, handling conversations, and configuring apps again. For a few Teams, that might be manageable, but repeating those steps across a large organization could become time-consuming.

I then came across the SysInfo Tenant to Tenant Migration Tool while comparing migration approaches. The information I found mentions custom and automated mapping, filters, duplicate removal, and delta migration, which could be useful when users continue working in the source tenant during the migration.

One thing I’m still trying to determine is how much of the original conversation history can realistically be transferred. The migration requirements can vary depending on the type of Teams data and Microsoft service/API limitations, so I wouldn’t want to assume that rebuilding a Team automatically brings everything with it.

For anyone who has handled a Microsoft Teams Tenant Migration, what did you consider the most important pre-migration check? Was it user mapping, SharePoint dependencies, chat data, permissions, or testing the destination environment?