Attachments are blocked after applying June 2017 update

After applying the June update for Outlook 2007, 2010, 2013 or Outlook 2016 (MSI) some attachments may be blocked from being opened. There are two issues here;

  • Attachments could get blocked as they are deemed “potentially unsafe attachments” even when they don’t have an unsafe file extension (like pdf, docx, xlsx).

    The blocked attachments are mentioned in the Infobar.
    The blocked attachments are mentioned in the Infobar.

    This issue applies to files that have two dots or an exclamation mark in front of their file extension;
    -test..txt
    -test!.txt

  • Attachments that are embedded (with the file icon shown in the message body) in an RTF formatted message, calendar item, contact item or task item can’t be opened. Trying to do so produces the error;
    • The program used to create this object is Outlook. That program is either not installed on your computer or it is not responding. To edit this object, install Outlook or ensure that any dialog boxes in Outlook are closed.

Error when trying to open an embedded attachment after applying the June 2017 update.
Error when trying to open an embedded attachment after applying the June 2017 update.

The Outlook Team has been made aware of these issues and is currently investigating these them. Outlook 2016 installed as part of Office 365 (Click-to-Run) is not affected. Current workarounds are;

  • For the first issue; Download the files via web mail. Exchange and Outlook.com users can use Outlook on the Web (OWA) for this, Gmail users can use the Gmail website, etc…
  • For the second issue, you can save the files to your Desktop (drag & drop also works) and open the files from there.
  • Uninstall the June update for your Outlook version. Please note that this is a security update, so uninstalling the update is only recommended when you know the risks and can’t use the other workarounds.