Symptoms

IE11 and SharePoint issue
 

Diagnoses

My company currently uses IE8 and is migrating to IE11.
Using IE8, I click on an activity in the K2 workflow list that is displayed on the SharePoint site. I am prompted to either save or open the .xml file. I click open and InfoPath 2010 opens and displays the form. This is the correct behavior and has worked like this for years.
Using IE11, I click on the same activity in the K2 workflow list on the same SharePoint site. I am prompted to save or open an ".aspx" file rather than a .xml file. I click open and InfoPath 2010 opens and displays an error. (not surprising)
I have saved a copy of that .aspx file (when using IE11) and have changed the file extension from .aspx to .txt so it could be uploaded.

Not sure if this is a server setting issue or an IE11 setting issue.

 

Resolution

At this moment we do not support IE 10 the lastest version supported is IE 9. You can check our Support Matrix for further references:

K2 BLackPearl
http://help.k2.com/blackpearl/support-matrix_Browser

SmartForms:
http://help.k2.com/smartforms/support-matrix_DesignTimeBrowser
http://help.k2.com/smartforms/support-matrix_RuntimeBrowser

You might want to try to add the site to the Compatibility view settings in IE11.