I haven't seen this problem but those who have are saying system restore to before these updates is the only thing that's worked for them :(
My IT Director and I spent some time chasing this issue down yesterday. It appears that the problem is associated with attachments that contain more than one period, or contain an exclamation mark. Also, if your attachment name exceeds the maximum length supported by your (sending) mail client, (is it 61 characters in some versions of Outlook?) then the client will "helpfully" truncate your excess final characters and (again) "helpfully" replace with 2-dots, triggering the issue.
For now, the work-around for our users has been to access their Outlook Web Access mailboxes and download their attachments from there.
It's really ticking us off that this broke, but at least the pain points have been manageable, as we've tried to communicate proactively.......here's what we sent the users on yesterday:
One of this week’s Microsoft (Security) updates has changed
you send an attachment with MULTIPLE periods in the name, your attachment will
be blocked by Outlook at the other end.
you send an attachment with an exclamation mark (!), your attachment will be
blocked by Outlook at the other end.
you add/invite a Calendar Meeting or Appointment with attachments, Outlook will
not allow opening the attachment(s).
you send/forward an attachment or message that has a title longer than 61
characters, Outlook will cut off the end and it will insert a couple of
periods, so then your message/attachment will be blocked.
Microsoft is aware of the issue, but have not yet provided
any solution or work-around. We will keep you updated.
If you receive a message that has a blocked attachment, you
can download it from our Outlook Web Access location:
and use your Windows username and password. You will be able to see
your INBOX and to download the attachment from this location.
this is helpful, or contact the I.S. & T. team at