Information on blocked email attachments

If you have been directed to this page from a University of Oxford email delivery failure message your email has been blocked

The person you sent the email to won’t have received it or know that you tried to send them a message.

In addition, if someone external to the University is sending you an email containing a high risk attachment this will also be blocked, and they will receive a failure notification.

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The University of Oxford blocks emails containing attachments with file extensions that are commonly used in email malware campaigns.

You must make sure that you don’t share personal or sensitive data insecurely, for example by email. See the University's Information Security website for the latest advice and guidance on keeping data secure.

OneDrive

Files in your OneDrive for Business cloud storage can be shared with internal and external recipients very easily and securely. Further details regarding OneDrive for Business, including links to how to use it, are provided on our OneDrive for Business overview page.

ZIP files

You can email the blocked file types if you save and email them as a ZIP file. We recommend that ZIP files are password protected.

See information about how to create a ZIP file below.

External File Sharing Services

See the University's Information Security website for the latest advice and guidance on using external services.

Non-University members

If you are external to the University of Oxford please get in contact with the file recipient to discuss your options. The recipient can, for example, set up a folder for you on the University’s file sharing service, OneDrive, where you can upload your file.

If you are sending public or non-sensitive information then you can use the built-in Windows ZIP tool:

  1. Press Start  + E to open Windows Explorer, and locate the file you want to send
  2. Right-click on the file, choose Send To > Compressed (zipped) folder
  3. The ZIP file will be created in the same folder as your original file

For sending files containing personal data or any other sensitive information, we recommend using 7zip to create an encrypted ZIP file:

  1. Download and install 7zip if it is not already available on your PC
  2. Right-click the file name and select 7-Zip and Add to archive…
  3. When prompted enter a filename for the ZIP file
  4. Select zip from the Archive format drop down list
  5. Enter a password (Information Security guidance is to use 16 characters or more)
  6. Select ZipCrypto as the Encryption method (AES-256 offers greater theoretical security, but ZipCrypto is more widely supported)
  7. Click OK
  8. Again, the ZIP file will be created in the same folder as your original file

Contact your local IT Support Staff or the Service Desk at IT Services.

Please contact the person you would like to send the file to for help.

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