Symptoms

  • Cannot see the attachment using a desktop client. Showing in webmail.

Solution


Microsoft usually suggests the following troubleshooting steps when users face a situation like this. I'd recommend cross-checking if you've already tried any of these before moving forward:

  • Check the Email Format: Sometimes, emails in Rich Text Format (RTF) can cause issues with attachments. Ask the sender to resend the email in HTML or Plain Text format.
  • Clear the Outlook Cache:
    1. Cached files might be causing the attachments to not display correctly.
    2. To clear the cache, follow these steps:
      1. Close Outlook.
      2. Navigate to C:\Users\[Your Username]\AppData\Local\Microsoft\Outlook.
      3. Delete all files in the Offline Address Books and Outlook folders (don't worry, these will be recreated by Outlook).
      4. Restart Outlook.
  • Disable Add-ins:
    1. Some add-ins might interfere with attachments.
    2. In Outlook, go to File > Options > Add-ins.
    3. Click on Go next to "Manage: COM Add-ins".
    4. Uncheck all add-ins and restart Outlook to see if the attachments appear.
  • Update Outlook:
    1. Ensure that Outlook is up to date. Go to File > Office Account > Update Options > Update Now.
  • Check Internet Connection:
    1. Ensure you have a stable internet connection, as issues with syncing could prevent attachments from loading on your computer.
  • Check antivirus or Security Settings 
    1. In Outlook, go to File → Options → Trust Center → Trust Center Settings → Attachment Handling and uncheck "Turn off attachment preview" if enabled.
    2. Some antivirus software blocks certain attachments (like .exe, .zip).

https://learn.microsoft.com/en-us/answers/questions/4650805/attachments-disappear-in-new-outlook-(windows)