If you've stumbled upon this post, you most likely experienced one of the nasty new MS Outlook security features shipped with the june 2017 security update, which blocks file attachments containing two or more consecutive periods or an exclamation mark in their name or extension. Here's the offending message:
Outlook blocked access to the following potentially unsafe attachments: filename.ext
As we already said, the culprit in this case is to be found in the latest MS security patches released after the ever-growing malware threat, which greatly excalated within the past few months. We're basically talking about a regression bug here, which is rather common in these kind of scenarios: the urge of preventing the user from compromising the system with potentially bad behaviours ends up with blocking a number of other legitimate and perfectly safe activities, such as opening most of these files.
Luckily enough, Microsoft acknowledged the issue and has already released a number of patches to overcome the issue. Too bad that they left out some Outlook builds - such as Outlook 2007, which is still vastly used worldwide - but at least it's a start.
Here are the patches currently available at the date/time of writing:
- June 27, 2017 - patch for Outlook 2010 (KB3015545)
- June 27, 2017 - patch for Outlook 2013 (KB3191849)
- June 30, 2017 - patch for Outlook 2016 (KB3213654)
It's worth mentioning that - at the time of writing - the Outlook 2010 patch works only for 64-bit builds, because the 32-bit version had some issues (!) which forced MS to retire it: hopefully they will release a good one in the next few days.
As soon as further patches will be released we'll update this post accordingly. Alternatively, you can always go to the Microsoft official page and get them directly from the source.
If the patch for your MS Outlook build isn't available yet, and/or if you're looking for a different workaround, you could try the following:
- Ask the sender to rename the attachment and send it again: he just need to avoid double periods or an exclamative mark after all...
- Switch to Mozilla Thunderbird or any other decent e-mail client. It's never too late to understand that Outlook is hardly the best e-mail client you can get, unless you're forced to use it because your company is setup that way (public folders, MS calendar and the other collaborative tools).
- Access your e-mail account using the WebMail client interface, which should be supported by any decent e-mail provider: e-mail clients are hardly affected by this kind of issues and should safely allow you to download the offending attachment(s).
If you come out with other viable workarounds, write them in the comments and we'll gladly add them to the list.
That's it for now: as always, we hope that these info will be useful for those who experienced the issue and are looking for a way to fix it!