Outlook blocked access to the following potentially unsafe attachments: xlsx or pdf or ppt or doc

Or, Outlook blocking attachments as “potentially unsafe file”

Or, Excel/pdf/ppt blocked in outlook client, opening file in web mail (OWA)

Problem Descriptions:

Suddenly user’s started reported that they are unable to receive attachments in their outlook application as its being blocked by outlook with error “Outlook blocked access to the following potentially unsafe attachments”. Files are being downloaded from web mail OWA with no issues.

Cause:

A knows/announced bug in MS patch KB3203467

https://support.office.com/en-us/article/Outlook-known-issues-in-the-June-2017-security-updates-3f6dbffd-8505-492d-b19f-b3b89369ed9b?ui=en-US&rs=en-US&ad=US

Solution:

A quick solution/workaround of this problem is to remove the bug oriented reported patch KB3203467 immediately from the affected machines and take a reboot.

Security Update for Microsoft Outlook 2010 (KB3203467) 32-Bit Edition

Security Update for Microsoft Outlook 2010 (KB3203467) 64-Bit Edition

Once you will remove this patch from the affected machine, your all attachments will come back to normal status.

Cheers, Please write me back if you have any query or feedback on this.