GmailでのGSMMO移行日付の修正
GSMMOの移行がGmailで間違った日付を表示する理由
GSMMO (Google Workspace Migration for Microsoft Outlook) uploads emails from PST files or Outlook profiles directly to Gmail using the Gmail API. While the Gmail API technically supports setting a custom INTERNALDATE during message insertion, GSMMO's upload process results in Gmail recording the upload timestamp as the INTERNALDATE for most messages. The original Dateヘッダー from the email is preserved, but the INTERNALDATE is overwritten.
In the Gmail Webインターフェース, this issue is partially hidden. Gmail web uses the Dateヘッダー from the email body for its display date, so most emails appear with the 正しい日付 in the browser. ただし、 the IMAP INTERNALDATE stored on the server is wrong. This becomes visible when ユーザー access their Gmail account through any IMAP client (Outlook, Thunderbird, Apple Mail) or when third-party tools query メールボックス via IMAP.
GSMMO is 通常 used by end ユーザー who are transitioning from Microsoft Outlook to Google Workspace. These ユーザー may not すぐに notice the INTERNALDATE issue if they primarily use the Gmail Webインターフェース. The problem surfaces weeks or months later when they install an IMAP client, set up a バックアップ tool, or when a コンプライアンス team runs a date-based search on メールボックス through Google Vault or IMAP-based archiving software.
Gmailへの影響
For Gmail web ユーザー, the visual impact is minimal because the Dateヘッダー displays correctly. ただし、 the corrupted INTERNALDATE affects several non-obvious areas. Gmail's IMAP SEARCH DATE command uses INTERNALDATE, so any IMAP-based tool or client that performs date searches against メールボックス gets incorrect results. Backup tools like MailStore, Veeam, or custom scripts that archive Gmail via IMAP record the 間違った日付s in their バックアップs.
Gmail's sorting within labels when accessed via IMAP uses the INTERNALDATE. Users who access their Gmail account from mobile IMAP clients or desktop email applications see an unsorted mess of emails all dated to the migration day. Google Takeout exports may also reference the INTERNALDATE for file naming or metadata, potentially creating confusing archives. The corrected Dateヘッダー is inside the message, but the INTERNALDATE governs how external tools and IMAP clients perceive the message timeline.
よくある質問
If Gmail web shows the 正しい日付, why should I fix the INTERNALDATE?
The INTERNALDATE affects IMAP clients, バックアップ tools, Google Vault コンプライアンス searches, and any third-party integration that connects via IMAP. Even if the Gmail web display is correct, the underlying data is wrong and can cause issues in バックアップ, コンプライアンス, and multi-client environments.
How does Redate.io fix GSMMO dates in Gmail?
Redate.io reads the original Dateヘッダー from each email, strips the GSMMO migration Receivedヘッダー, and re-inserts the email with the correct INTERNALDATE matching the 元の日付. The original email is moved to a バックアップ label for safety.
Will the fix change how emails appear in Gmail web?
いいえ。 Gmail web already shows the 正しい日付 (from the Dateヘッダー). The fix corrects the INTERNALDATE so that IMAP clients also display the 正しい日付. The Gmail web experience remains unchanged.