Script Download: FixIssuesDescribedinKB982021(VBScript).ziphttp://gallery.technet.microsoft.com/scriptcenter/Script-to-fix-the-issue-db85fc6f
You have Microsoft Lync Server 2010 Front-End Server or Microsoft Lync Server 2010 Edge Server installed on Windows Server 2008 R2 with NTLM SSP set to 'Require 128-bit encryption'. This will prevent pre-Windows 7 clients from joining online meetings. You can run this script to check and change the NTLM setting to fix this issue.
You can find more All-In-One Script Framework script samples at http://aka.ms/onescriptingallery