Fix Manual IMAP Copy Dates in Gmail
Why Manual IMAP Copy Shows the Wrong Date in Gmail
Manual IMAP copy to Gmail involves adding both a source IMAP account and the Gmail account to an email client (Outlook, Thunderbird, or Apple Mail) and copying messages between them. When the email client uploads messages to Gmail via IMAP APPEND, Gmail records the upload timestamp as the message's INTERNALDATE. The email client does not pass the original INTERNALDATE from the source server because most clients do not support this during copy operations.
Gmail's IMAP handling introduces an additional complication. Gmail processes uploaded messages through its own pipeline, adding a Received header that contains the Gmail IMAP gateway timestamp. This Received header becomes the topmost entry in the header chain. While Gmail's web interface uses the Date header for display (potentially showing correct dates), every IMAP client that subsequently connects to the Gmail account reads the corrupted INTERNALDATE.
Users who manually copy emails to Gmail often do so when consolidating multiple email accounts or when moving from a less common email provider that is not supported by standard migration tools. The simplicity of drag-and-drop in an email client masks the underlying date corruption that occurs at the IMAP protocol level. The problem becomes apparent when the user checks their Gmail account from a different client or when an IMAP-connected backup tool archives the wrong dates.
How This Affects Gmail
In Gmail, the impact follows the familiar split: the web interface may show correct dates (from the Date header) while IMAP clients show the copy date (from the INTERNALDATE). Users who access Gmail only through the web browser may not notice the issue. Users who use Outlook, Apple Mail, or Thunderbird connected to Gmail via IMAP see the copy date for all manually transferred messages.
Gmail's label system preserves the labels applied during the copy, but the sorting within labels uses the INTERNALDATE when accessed via IMAP. IMAP clients that sort by server date display the copied messages out of their original chronological order. Google Takeout exports and third-party backup tools record the copy date as the message date, creating permanent inaccuracies in exported archives. For users who manually consolidated years of email from multiple accounts into Gmail, the date corruption can affect a significant portion of their entire email history.
Frequently Asked Questions
I used Thunderbird to copy emails to Gmail. Are my dates affected?
Yes. Thunderbird, like all email clients, uses IMAP APPEND without specifying the original INTERNALDATE when copying between accounts. Gmail sets the INTERNALDATE to the upload time. Redate.io can fix these dates regardless of which client was used for the copy.
Can I fix dates only for manually copied emails, not my entire Gmail?
Yes. Redate.io scans the mailbox and identifies emails where the INTERNALDATE does not match the Date header. Only affected messages are flagged for fixing. Emails that were natively received by Gmail (with correct dates) are left untouched.
Does the fix work if I copied emails from multiple source accounts?
Yes. Redate.io fixes dates based on the original Date header of each email, regardless of where it was copied from. Multiple source accounts consolidated into a single Gmail account can all be fixed in one scan-and-fix operation.