Outlookでの手動IMAPコピー日付の修正
手動IMAPコピーがOutlookで間違った日付を表示する理由
Many ユーザー and 管理者 attempt to migrate emails between メールサーバーs by adding both IMAP accounts to Outlook and dragging or copying messages from one account to the other. This manual approach uses Outlook as an intermediary: Outlook downloads the email from the source IMAP server, then uploads it to the destination IMAP server using the IMAP APPEND command. During this upload, 宛先サーバー adds a new Receivedヘッダー with the current timestamp.
The manual IMAP copy approach has no mechanism for preserving the original INTERNALDATE. Unlike dedicated migration tools (which at least attempt to set the INTERNALDATE during APPEND), Outlook's copy operation does not pass a date parameter to 宛先サーバー. The destination server sets the INTERNALDATE to the upload time, and adds its own Receivedヘッダー. Both date sources now reflect the copy date rather than the original received date.
Users who perform manual IMAP copies often do so because they believe it is the simplest approach, or because they are moving a small number of emails. ただし、 even a small manual copy can corrupt dates for hundreds of messages if an entire folder is selected. The 日付の破損 is not apparent until after the copy is complete, when the ユーザー notices that all copied messages now show the copy date in Outlook's received column.
Outlookへの影響
After a manual IMAP copy, Outlook displays the copy date for all transferred messages. The "Received" column shows when the message was copied, not when it was originally received. If the ユーザー deleted the originals from ソースサーバー, there is no way to see the 正しい日付s in Outlook without fixing the headers.
The impact is identical to a migration tool-caused 日付の破損: sorting, searching, and filtering by date all operate on the copy timestamp. Outlook's date-based groupings (Today, Yesterday, This Week, etc.) are disrupted. Unlike migration tool scenarios that 通常 affect an entire メールボックス, manual IMAP copy 日付の破損 may affect a subset of メールボックス (only the folders or messages that were manually copied), creating an inconsistent mix of correctly-dated and incorrectly-dated messages within the same メールボックス.
よくある質問
I only copied a few folders manually. Can Redate.io fix just those?
はい。 Redate.io scans the entire メールボックス and identifies only the emails with corrupted dates (where the INTERNALDATE does not match the original Dateヘッダー). It fixes only the affected messages, leaving correctly-dated emails untouched.
Is manual IMAP copy worse than using a migration tool?
In terms of 日付の破損, the result is the same: 宛先サーバー stamps messages with the upload date. Manual IMAP copy through Outlook is actually worse in one respect: it does not attempt to set the INTERNALDATE, whereas some migration tools at least try to preserve it.
Can I prevent 日付の破損 when copying emails between IMAP accounts in Outlook?
Outlook does not support setting INTERNALDATE during IMAP APPEND. There is no way to prevent 日付の破損 when using Outlook to copy between IMAP accounts. If dates were corrupted, Redate.io can fix them after the fact.