File types blocked in Gmail

There are a number of reasons why you may see the "This message was blocked because its content presents a potential security issue" error in Gmail. Gmail blocks messages that may spread viruses, like messages that include executable files or certain links.

Messages that have attachments

To protect you against potential viruses and harmful software, Gmail doesn't allow you to attach certain types of files, including:

  • Certain types of files, including their compressed form (like .gz or .bz2 files) or when found within archives (like .zip or .tgz files)
  • Documents with malicious macros
  • Password protected archives whose content is an archive

Note: If you try to attach a document that is too large, your message won't send. Learn more about attachments and file size limits.

To protect your account, Gmail doesn't allow you to attach certain types of files. Gmail often updates the types of files not allowed to keep up with harmful software that is constantly changing. Some examples include: 


If you're sure the file is safe, you can ask the sender to upload the file to Google Drive. Then send it as a Drive attachment.

Messages that don't have attachments

Sometimes messages are blocked when you don't include any attachments.

This can happen when you include content, images, or links that might share viruses.

Not receiving email from one sender

Here’s what to do if you or your users aren’t receiving email from a particular sender.

Important: If users at your domain aren’t receiving any email, make sure that your domain is set up to receive email.

Step 1: Check if the email was delivered to G Suite

As a G Suite administrator, you can find missing messages using Email Log Search. If a message was delivered to Google’s server, the tool will let you know of its whereabouts for up to 30 days.

  1. In your Google Admin console (at

  2. Go to Reports > Audit > Email log search.

    Requires having the Email log search administrator privilege.

  3. Next to Date, select a date range from the list.
  4. In the search fields, enter any information you have and click Search.
  5. Under Subject (or Message ID), click any of the subjects to see message details and delivery status.
    • If your missing message is listed but you still can’t find it, try these common fixes for missing messages.
    • If you don’t see anything about the message, it wasn’t delivered to Google’s servers.

Step 2: Contact the sender of the missing message

If the missing message never reached Google’s servers (see step 1 above), contact the sender and ask them to verify what happened to the message.

If missing messages are from a web form

This issue is commonly caused by a default setting in the web form. In this case, your form handles messages as if your website and mail servers are both hosted at the same place. As a result, your local mail never leaves your web host.

To fix it, contact your web host. Your host might need to adjust your form’s delivery settings to always route your messages to Google’s servers. If needed, you can direct them to your MX record values.

Related topics