Every migration has a moment when the old system is switched off, and that is when old data is lost. Before you move, decide what you will migrate, what you will archive, and what you will let go, and write down when the old vendor deletes data. Microsoft 365 data goes through 30 days “Expired” and 90 days “Disabled” before deletion for most subscriptions. Google says cancelled Workspace data is deleted and can’t be restored.
Steps before you switch systems
- Inventory the old system: mailboxes, shared drives, channels, users who have left, and how many years of data.
- Decide per data set: migrate, archive or let go. Check legal and tax retention rules first.
- Note the vendor’s deletion timeline and set a date to finish exports well before it.
- Export and verify that archives open and are complete.
- Switch users over, then shut the old system down only once the exports are checked.
Where company records fit
Teams usually migrate recent data and archive the rest, then pay to store an archive nobody opens. Before you do, look at what the archive is: years of email, chat, tickets and documents. Some AI developers license de-identified copies of exactly this kind of record. Decide that before the old system is shut down, because once a vendor deletes data, it is gone.
Guides in this section
How to export Google Workspace data before you cancel
Google's Data Export tool requirements and timing, what happens to data after cancelling Workspace, and the resubscribe windows Google publishes.
How to export Slack data, plan by plan
What Slack exports on Free, Pro, Business+ and Enterprise, the free plan's 90-day and one-year limits, and why deleting a workspace is permanent.
What happens to Microsoft 365 data when the subscription ends
Microsoft 365's expired, disabled and deleted stages, how long each lasts, what cancelling changes, and how to keep mailboxes without paying for licenses.
What to do with old email archives when you move to Microsoft 365 or Google Workspace
Migrate, archive or let go: how to handle years of old email when switching between Google Workspace and Microsoft 365, and when the old vendor deletes it.
Exporting your Salesforce data before you move or leave
Salesforce's Data Export Service by edition, the 48-hour download window, why queuing a new export removes old files, and what to export besides records.
Slack to Teams: what happens to your message history
What Slack lets you export on each plan, what Microsoft Teams can and cannot import, and how to keep years of Slack history when you switch.