Fix BitTitan Migration Dates in Microsoft 365
Why BitTitan Migrations Show the Wrong Date in Microsoft 365
When BitTitan MigrationWiz migrates mailboxes into Microsoft 365, it uses the Exchange Web Services (EWS) or IMAP protocol to upload messages to the destination tenant. During this upload, Microsoft 365's mail infrastructure stamps each message with a new Received header containing the migration timestamp. This header becomes the most recent entry in the email's header chain.
Microsoft 365 stores this timestamp as the message's INTERNALDATE. Every client that connects to the M365 mailbox (Outlook desktop, Outlook on the web, Outlook mobile, and third-party IMAP clients) reads this INTERNALDATE to determine when the message was received. As a result, the entire mailbox displays the migration date for every email, regardless of when the message was originally sent or received.
For organizations migrating to Microsoft 365 from on-premises Exchange, Google Workspace, or other platforms using BitTitan, this date corruption affects every migrated mailbox simultaneously. IT teams face a wave of support tickets from users who can no longer find emails by date across any of their M365 applications.
How This Affects Microsoft 365
In the Microsoft 365 ecosystem, the impact extends beyond a single client. Outlook on the web (OWA), Outlook desktop, Outlook for Mac, and the Outlook mobile apps all display the wrong date. Microsoft's Copilot and AI features that reference email timelines also produce incorrect results because they rely on the same corrupted date metadata.
Compliance and eDiscovery workflows in Microsoft 365 are particularly affected. Litigation holds, retention policies, and compliance searches that filter by date range return inaccurate results. Administrators who need to produce emails from a specific time period for legal or audit purposes cannot rely on the displayed dates. Microsoft 365's built-in search and the Security & Compliance Center both reference the corrupted INTERNALDATE, making accurate date-based queries impossible without first fixing the underlying data.
Frequently Asked Questions
Does BitTitan MigrationWiz corrupt dates when migrating to Microsoft 365?
Yes. BitTitan MigrationWiz adds a Received header during the migration process that overwrites the displayed date in Microsoft 365. This is a known side effect of IMAP-based migration and affects all M365 clients and services that reference the message date.
Will fixing dates affect Microsoft 365 compliance and retention policies?
Redate.io restores the original dates, which actually improves compliance accuracy. After the fix, retention policies, eDiscovery searches, and litigation holds reference the correct original dates rather than the misleading migration timestamps.
Can Redate.io fix dates across all Microsoft 365 apps at once?
Yes. Redate.io fixes the email at the server level by correcting the Received headers and INTERNALDATE. The corrected date then appears automatically in Outlook desktop, OWA, Outlook mobile, and any other client connected to the Microsoft 365 mailbox.