For IT Consultants ·
What you'll accomplish
A 60-mailbox tenant migration used to mean an afternoon spent manually sequencing which mailboxes, shared drives, and license groups move in what order. ChatGPT's data analysis feature reads the raw inventory export straight from a spreadsheet and returns a phased plan with sequencing and rollback steps for each phase, in minutes rather than half a day.
What you'll need
Pull your inventory export from the source tenant's admin center as a CSV: mailbox count, license assignments, shared drive or SharePoint volume, and any mail flow rules that need to carry over. Before doing anything else, open the file and replace the user name column with generic role labels ("Sales-1," "Sales-2," "Finance-Lead") or just a row number.
What you should see: A spreadsheet where every row still has its mailbox size and license type, but no employee's actual name or email address.
Troubleshooting: If your PSA or RMM tool exports directly to CSV, use that instead of retyping the admin center's screen. Fewer manual transcription steps means fewer errors in the plan that follows.
Go to chatgpt.com and sign in. Start a new conversation dedicated to this migration so you can return to it later without your other chats mixed in.
What you should see: An empty chat window with a message box and a "+" icon at the bottom.
Click the "+" icon (sometimes shown as a paperclip) at the bottom of the message box and choose "Upload from computer" or "Add photos and files." Select your cleaned inventory file.
What you should see: The file appears as an attachment above the message box. ChatGPT recognizes spreadsheet data automatically and will write and run analysis code behind the scenes when you ask a question about it, without any separate toggle to switch on.
Troubleshooting: The free plan allows only a few uploads per day. If you hit that limit mid-session, wait until the next day or upgrade for that week if you're on a deadline.
Describe the migration type (tenant to tenant, on-prem to cloud, or a Google Workspace to M365 move) and ask for a plan sequenced by risk and dependency, with a rollback step attached to each phase.
What you should see: A response broken into phases (for example: pre-migration validation, pilot group, bulk mailbox move, shared drive migration, cutover, post-migration cleanup), each with a rollback note.
The inventory export won't capture everything relevant, mail flow rules, third-party app integrations, or custom domains, for example. Ask directly what additional information the plan is missing.
What you should see: A list of gaps, such as "this plan assumes no custom mail routing rules; confirm none exist before finalizing the cutover phase."
Before you rely on any part of this plan, open the source tenant's admin center and spot-check the mailbox count, license totals, and shared drive volume the plan is built on against what the console actually shows right now.
What you should see: Numbers that match, or a discrepancy you need to fix before the migration proceeds. Exports go stale fast when a tenant is still active, so this check catches drift between when you pulled the export and when you're about to act on the plan.
Troubleshooting: If the counts don't match, re-pull the export and re-run Step 4 rather than patching the old plan by hand.
Risk-first plan:
Rank the riskiest parts of this migration first, based on mailbox size,
license complexity, and shared drive volume in the attached export.
Timeline estimate:
Based on this mailbox count and data volume, give a rough range for
how long each phase should take, and note what would extend it
(large mailboxes, litigation holds, custom domains).
Pilot group selection:
From this inventory, suggest which 3-5 mailboxes make the best pilot
group for testing the migration process before the full cutover.
Rollback checklist:
Write a rollback checklist for the cutover phase specifically: what to
check first if mail stops flowing within an hour of cutover.