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ElliotMelb's avatar
ElliotMelb
Copper Contributor
May 28, 2026

Important email completely disappeared when sending

I am using office 365. I spend a lot of time writing this email.  It included one other email as an attachment.  When I sent it it simply disappeared. The only sign that it had ever existed is the following failure message:

Your message did not reach some or all of the intended recipients.

 

Subject: Re: Mr Elliot Gingold - quote for recliner - Urgent

Sent: 28/05/2026 5:18 PM

 

The following recipient(s) cannot be reached:

 

S****** 28/05/2026 5:26 PM

****** on 28/05/2026 5:26 PM

E******x on 28/05/2026 5:26 PM

This message could not be sent. Try sending the message again later, or contact your network administrator.

 

__________________________________________________

 

Diagnostic information for administrators:

__________________________________________________

 

Error is [0x80040305-0x00000000-0x00000000].

 

Failed to upload attachments to server (error 0x80040305).

 

Submit-Message failed: message id(1), failure enum(29), HResult(0x80040305), EC(0).

 

*(Names of recipients hidden)

I cannot try to send it again as it has completely disappeared.  No trace of it in Drafts, Outbox, Sent Items, Deleted Items, or anywhere else!

The only mistake on my part I can find is that I am now using New Outlook!!

 

Is there any way I can get my email back again? Or is the time I spent on witing this email gone up in smoke??

Elliot

 

 

office 365

1 Reply

  • GuidovanDijk's avatar
    GuidovanDijk
    MCT
    May 30, 2026

    Hi,

    Unfortunately, the error message suggests the message was never successfully submitted to Exchange Online because Outlook failed while uploading the attachment:

    Failed to upload attachments to server (0x80040305)

    When this happens, Outlook may create the message locally, attempt to upload it, then remove the local copy after the send operation fails. In some cases, the message never reaches Drafts, Sent Items, or the server at all.

    Before assuming it is lost, I would check the following:

    1. Recover Deleted Items
      • Outlook → Deleted Items → Recover items deleted from this folder.
    2. Search all Outlook folders
      • Search for a unique word or phrase from the email body.
      • Also search for the attachment name.
    3. Check Outlook Web App (OWA)
      • Sign in via Outlook on the web
      • Check Drafts, Sent Items, Deleted Items, and Recover Deleted Items.
    4. Check the local Outlook cache
      • If you were using the New Outlook desktop app, the message may have been cached locally before the failure occurred.
      • Look in:
        • Drafts
        • Sync Issues folders (if using classic Outlook)
        • Recovered Items
    5. If the attached email was recently received
      • Open that attached email and check whether any of the text you wrote was accidentally saved as notes, comments, or a draft reply.

    If the message cannot be found in Outlook Desktop, Outlook Web, Deleted Items, Recover Deleted Items, or a search of all folders, then the message content was likely never committed to the mailbox and may not be recoverable.

    Going forward, if you're using New Outlook, consider enabling automatic draft saving and, for lengthy emails, drafting them in Outlook on the web or a document first. There have been reports of draft and attachment-related issues in some New Outlook builds.