I’m looking at a migration involving multiple users and I’m trying to understand how others handle permissions and mailbox targeting.

One feature I noticed in DRS Softech PST to Office 365 Migration Tool is its Assign Impersonation Rights option. According to the product documentation, it can be used to import PST files into both main and sub-accounts, with the ability to upload a CSV containing account details.

That seems interesting for administrators who don't want to handle every mailbox separately. The tool also supports selecting Mailbox, Public Folder, or Online Archive as destinations, so there appears to be some flexibility in how the imported data is organized.

I’d also want to avoid importing the same messages repeatedly during a staged migration. The incremental migration and duplicate-removal options seem designed for that situation.

Has anyone used impersonation or CSV-based mailbox mapping for a PST migration? I’m especially interested in practical experiences with permissions and large batches.