OutlookでのGSMMO移行日付の修正
GSMMOの移行がOutlookで間違った日付を表示する理由
GSMMO (Google Workspace Migration for Microsoft Outlook) is Google's official tool for migrating PST files and Outlook profiles into Google Workspace. GSMMO reads emails from the local Outlook PST or Exchange profile and uploads them to the ユーザー's Google Workspace account via the Gmail API. During this upload, Gmail stamps each message with the current upload timestamp as the INTERNALDATE and adds a Receivedヘッダー reflecting the 移行日.
When ユーザー then connect Outlook back to their Google Workspace account via IMAP (or Google Workspace Sync for Outlook), Outlook reads the IMAP INTERNALDATE and the topmost Receivedヘッダー. Both now contain the 移行日. The emails that previously displayed 正しい日付s in the local PST or Exchange profile now show the GSMMO 移行日 in Outlook's received column.
GSMMO migrations are 特に frustrating because ユーザー often initiate the migration themselves, following Google's migration guide. They expect the migration to be transparent, preserving their email history exactly as it was. Instead, they discover after the migration that every email in their メールボックス now shows the date they ran GSMMO. The self-service nature of GSMMO means the problem often affects individual ユーザー who lack the technical expertise to diagnose or resolve the issue.
Outlookへの影響
Users who migrated from Outlook (PST or Exchange) to Google Workspace using GSMMO and then reconnected Outlook to the Google Workspace account via IMAP face a double disappointment. Their carefully organized, date-sorted メールボックス in Outlook now shows every email as received on the GSMMO 移行日. The chronological order they depended on is completely destroyed.
Outlook's conversation view, which groups related messages by thread, still functions based on subject and message-ID. ただし、 the date displayed next to each message in the conversation is wrong, making it difficult to understand the timeline of a conversation. Calendar invitations and meeting responses in the migrated メールボックス show the 移行日, which can cause confusion when reviewing past scheduling decisions. Outlook's Journal and Activity features that reference received dates also display incorrect timelines.
よくある質問
Is GSMMO supposed to preserve email dates?
GSMMO preserves the original Dateヘッダー within the email body, but it cannot prevent Gmail from setting the INTERNALDATE to the upload timestamp. When Outlook connects to the Google Workspace account via IMAP, it reads the INTERNALDATE, which shows the 移行日.
I migrated my own メールボックス with GSMMO. Can I fix it without IT help?
はい。 Redate.io is designed for both individual ユーザー and 管理者. Individual Google Workspace ユーザー can connect their account, scan for affected emails, and fix the dates without needing domain-wide admin privileges.
Can Redate.io fix GSMMO dates for both Outlook and Gmail at the same time?
Redate.io fixes the email at the サーバーレベル (in the Google Workspace account). Once the INTERNALDATE and Receivedヘッダーs are corrected, the fix is visible in Outlook, Gmail web, Apple Mail, and any other client connected to the account.