First off, is this on all encrypted sites, or just this particular site? If it's only this particular site, then you should be contacting the site administrator.
Secondly, if it's happening on multiple sites, test the sites with other browsers (Firefox, Chrome, Opera, Seamonkey, etc.). If the same issue happens, make sure you have the latest version of Adobe Reader installed.
Finally, if it's only happening in IE, then a) make sure you have the latest version of IE installed, b) double-check with the site administrator to find out if they have any issues with particular IE versions (certain colleges, for example, will have issues with their online homework submission websites not always working well when IE is upgraded by Microsoft to a new version), and c) consider making a mental reminder to not use IE if you need to view an encrypted PDF.
It's happining on all Encrypted web sites in a VDI. IE 10, can't use 11 due to other web related issues. I can't really have my users on anything other then IE becuase it's this company's standard and where they want everyone. Adobe is the current relesae. I actually removed, reinstalled and get the same results.
Here's the kicker, it works fine outside the VDI on her local PC and opens in Adobe not IE. When I set it to open directly in Adobe in the VDI, nothing happens. Reader does not start, document does not open, nothing happens.