I'm planning a tenant-to-tenant Microsoft 365 migration for a customer with roughly 100 users. Their PCs use local profiles, with no domain or Intune management, but NinjaRMM is installed everywhere, so I could deploy a PowerShell script.
For smaller customers, we normally have users call in or send an engineer onsite to recreate Outlook profiles and reconnect OneDrive. This time I'm considering automating the process by resetting the Outlook mail profile, clearing old credentials, and resetting OneDrive. I've used BitTitan for migrations and know DeploymentPro can automate profile setup, but adding another per-device license is difficult to justify.
How do you handle Outlook and OneDrive reconfiguration at this scale? Are there important details around cached credentials, autocomplete data, script context, or rollout timing that I should plan for?
5 Answers
For a client without a domain or Intune, scripting through the RMM is a sensible approach. Run the script in the logged-in user’s context, remove the old Outlook profile, clear stale Microsoft 365 credentials from Credential Manager, unlink OneDrive, and let the apps authenticate to the new tenant. Running as SYSTEM can cause problems because the relevant settings are under HKCU and the user’s OneDrive state.
The basic registry locations are usually HKCUSoftwareMicrosoftOffice16.0OutlookProfiles for Outlook and HKCUSoftwareMicrosoftOneDriveAccountsBusiness1 for OneDrive. Check the Office version before hard-coding paths, and don’t forget cached credentials—old Microsoft Office or tenant credentials can cause repeated sign-in prompts even after the profile is recreated.
At this size, I’d stagger the deployment rather than reset everyone at once. Rebuilding every Outlook OST and OneDrive cache simultaneously can overwhelm the customer’s internet connection. Use RMM groups or first-login waves over several days, and handle people who are away, traveling, or working shifts separately.
A scripted reset works, but it won’t automatically preserve everything users care about. Autocomplete is the common complaint. Migration tools such as DeploymentPro can move autocomplete data and guide users through creating the new profile, which may justify the cost if minimizing user disruption matters more than keeping the process fully in-house.
That was my experience too: the tool is mostly buying a smoother wizard and preservation of user-specific data. For a no-domain, no-Intune customer, a carefully tested script is usually enough if you document what will and won’t carry over.
For larger migrations, onsite technicians can still be effective if the environment is unfamiliar or the RMM wasn’t available beforehand. One team migrated around 100 users by handling Windows profiles first, then Office apps, Outlook, and OneDrive. Most were completed in a day, with the remaining users processed later because they were absent or on different shifts.
Also make sure the script runs only after the MX cutover is confirmed. Users should be warned that Outlook and OneDrive will ask them to sign in again, otherwise you’ll still get a wave of support calls.