SharePoint 2010 Troubleshooting: July 2013 Windows Security Update Breaks SharePoint XSLT System Web Part Pages

Last week a Microsoft Windows Security Update was applied to a production server running Windows Server 2008 and SharePoint 2010.  Following this patch, content owners using the Insert Link > from SharePoint to insert a link to a page, list item, or documents started receiving an error on the system generated dialog box which is using AssetPortalBrowser.aspx layout. 

Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Microsoft SharePoint Foundation-compatible HTML editor such as Microsoft SharePoint Designer. If the problem persists, contact your Web server administrator.

After researching the error, we traced it back to an error in the XSLTDateview web part.  This is a system-generated page so we knew that a content owner could not have modified the XSLT for this web part. Thinking that maybe something had changed to a XSLT style sheet, we created a new web application with a new database. Testing proved that the dialog box to select images was still broken on a clean environment with no modifications. This led us to believe that it was farm wide. 

This led us to believe something had changed on the server level.  A quick restore of a development VM snapshot prior to patching proved that everything worked before the server was patched.  However, reverting a production server to a VM backup was not going to be easy so we decided to remove each security one by one until we identified the problematic update:

Security Update for Microsoft .NET Framework 3.5.1 on Windows 7 and Windows Server 2008 R2 SP1 for x64-based Systems (KB2844286)

Removing the above security update and doing a quick reboot of the web servers fixed the dialog box.  We did have a support ticket open with Microsoft and they stated that this is the recommended fix at this time.

Another great example of why you should patch your development servers and test before patching production.