I’ve seen a number of emails recently which appear to be from Microsoft with advice about a critical patch you need to install.  

The latest one was titled “Install Critical Update for Microsoft Outlook” regarding patch “officexp-KB910721-FullFile-ENU.exe“

Delete these emails – they’re not legit!   MS would never email you with advice like this as you should be using automatic updates to receive any patches from them.

TIP:

If you hover your mouse over the link in the email – you’ll see that it doesn’t actually link back to Microsoft – instead it links back to a random address that “looks” like Microsoft.  In my example it was linking to a site along the lines of update.microsoft.com.1lfx.mx.com.   If you don’t pay attention – it’s easy to miss the “1lfx.mx.com” and think that this is linking to MS.