Issue
A user receives an email with some PDF files attached. Attachments are not accessible in MS Outlook 2010. Instead, following message is displayed:
Outlook blocked access to the following potentially unsafe attachments: Important! Invoice 721.pdf, Important! Invoice 721.pdf.
Workaround
This MS Outlook behaviour is a bug introduced by 13 June 2017 Outlook Security Update, and affects all recent versions of MS Outlook (2007 - 2016). In this particular case the bug was triggered by attachments having an exclamation mark in their file names and the offending update was KB3203467.
I don't believe there is an easy way to open such blocked attachments from within Outlook. I expect Microsoft to provide a proper fix via another update some time soon. In a mean time here a few workarounds that come to mind:
- Ask the original sender to remove exclamation marks from file names and resend the email.
- Open email from a webmail or another email client.
- Remove the offending update. Not recommended as the update fixes some remote code execution vulnerability.
June 2017
Outlook 2010
Windows 7 Pro
