Scrupuli

This problem needs the intervention of an experienced Windows user. It is not something that a user should attempt to repair without knowledge of ActiveX controls and the registry.

Here is the technical analysis of the problem.

Lync 2013 uses Internet Explorer to display the shared desktop. The desktop is displayed by a little add-on (an ActiveX control). If this ActiveX control cannot run, then you will only see the blank white area.

Internet Explorer can prevent ActiveX controls from running. In particular, any ActiveX control can be marked COMPAT_EVIL_DONT_LOAD and that ActiveX control will never be activated. A PC’s list of “evil” ActiveX controls is kept up to date by Microsoft Update, and can also be updated by third party security software.

ActiveX controls generally have an identity code. An ActiveX control that has not been assigned an identity code is treated as if its identity code is {00000000-0000-0000-0000-000000000000}. This ID has reportedly been used by several pieces of malware, including Commonname, CoolWebSearch, and TencentAddressBar.

The anti-spyware program Spybot – Search & Destroy protects against these malware by marking ActiveX control {00000000-0000-0000-0000-000000000000} as “evil” when it immunizes the PC.

Microsoft .NET add-ons must pass Internet Explorer’s safety check, and they have no identity code. This includes the add-on used by Lync 2013 to display the shared desktop.

As a side effect, then, of having previously run Spybot – Search & Destroy immunization on a PC, Lync 2013 running on that PC cannot display a shared desktop.

This can be undone by removing {00000000-0000-0000-0000-000000000000} from the list of “evil” ActiveX controls. To accomplish this, delete the registry entry HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Internet Explorer\ActiveX Compatibility\{00000000-0000-0000-0000-000000000000} (if using a 32-bit Lync 2013 on a 64-bit Windows) or HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{00000000-0000-0000-0000-000000000000} (if running a 32-bit Lync 2013 on a 32-bit Windows or a 64-bit Lync 2013 on a 64-bit Windows).

This information comes from the sources linked above and below, and is confirmed by my own testing.

• Mike F Robbins Computing Solutions: Unable to View a Shared Desktop or Application in a Microsoft Lync 2013 Meeting
• msunified.net: Technical blog about Exchange, OCS and Lync by Ståle Hansen: You see only a white screen when viewing Lync 2013 desktop sharing
• Spybot – Search & Destroy Forums: Thread: ActiveX and CLSID {00000000-0000-0000-0000-000000000000}
• How-To Geek: What ActiveX Controls Are and Why They’re Dangerous