To work around the issue follow these steps.
As an example scenario, when dealing with TeamX (Team or M365 Group) and initial migration of the source Team already created one in the target.
- in target tenant Admin Center, check what SP URL TeamX is linked to
- delete TeamX
- go to SharePoint Admin and make sure that TeamX SP site is deleted from Active Sites and not present in Deleted Sites
- if it's in Deleted Sites, see if this can be purged.
- if not, use PowerShell to delete the site
SP sites w/ Teams that cannot be deleted from SP recycle bin. Way to delete SP and not Teams mig? (4256777) (quest.com)
Once target TeamX/SP site are gone, create a new TeamX manually in the target. It'll create SP site as well and you can modify URL if needed.
From ODM UI, remove TeamX and rediscover the site.
Either run a discovery for the entire tenant or only for the specific Team, using CSV file.
Map source TeamX to the target TeamX using CSV file. For this, you'll need to populate it as in the 1st line (header):
Then mailnicknames in format source_team_mailnickname,target_team_mailnickname in next line, and so forth (if mapping multiple teams at once)
Once TeamX is mapped, go to SharePoint in ODM and verify if /sites/sourceSP_path mapped to /sites/targetSP_path.
If not, map them using CSV file as well.
Next step: run TeamX provisioning with options set to Merge.
This step is important as it will create the entire structure in the target tenant. Make sure that there are no errors.
Once provisioning is done, migrate the TeamX. It should migrate the whole content.
Once the task is complete, verify if SharePoint content was migrated. If not, drill down to List level in the SharePoint, and migrate the List specifically (make sure it's pointing to the proper target SharePoint URL).