This update fixes the following attachment issues that were reported after the release of the June update. For more information, see Outlook known issues in the June 2017 security updates.
Issue 1
When you open an attachment whose file name includes an ellipsis (...) or an exclamation point (!), the files are blocked, and you receive a warning message.
Issue 2
If an email message includes an attached email message, and the subject line of the attached message ends with an unsafe file name extension (as listed in the Blocked attachments in Outlook Office webpage), the email attachment is blocked for recipients.
Issue 3
When you open attachments that use ShowLevel1Attach, you receive the following error message:
One or more objects in this file have been disabled due to your policy settings