We have LYNC 2010 merged topology with OCS 2007 R2. Few of the OCS 2007 R2 users moved onto LYNC pool. Only portion of these LYNC users client has been upgraded to LYNC 2010 client and other LYNC Pool users are still using OCS 2007 R2 client and Live Meeting.

We are having an issue with desktop sharing / application sharing when using LYNC WebApp to join LYNC meetings.

Below are the different scenarios:

OCS User: Unable to Join LYNC Meeting using WebApp with AD credentials, Got error "There was an error while joining the conference. Please contact the meetingt organizer".

Joining as Guest worked fine and able to share desktop and applications without any issue.

LYNC User (with NO Lync client ): Able to join LYNC meeting using WebApp with AD credentials, however failed to share desktop or applications with "Your sharing session could not start" error message.

Log from WebApp client:

"10/15/2013-09:20:08.920 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareManager.get_CanAttemptAppShare) Sharing not allowed at this point as both connect and disconnect are disabled
10/15/2013-09:20:08.920 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareManager.get_CanAttemptAppShare) Sharing not allowed at this point as both connect and disconnect are disabled
10/15/2013-09:20:08.920 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareManager.get_CanAttemptAppShare) Sharing not allowed at this point as both connect and disconnect are disabled
10/15/2013-09:20:08.936 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareSession.OnConnectCallback) Sharer type appsharing session connect failed. StatusCode=7, DiagCode=0
10/15/2013-09:20:08.952 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareNotify.ShowNotification) Your sharing session could not start.
10/15/2013-09:20:08.983 0001TL_WARN(TF_COMPONENT)::(CollaborationApi,AsHostEndpointWin.Microsoft.Rtc.Internal.Collaboration.ApplicationSharing.Media.IAsHostEndpoint.StopSession) StopSession ignored, plugin = null || state==stopped
10/15/2013-09:20:08.983 0001TL_WARN(TF_COMPONENT)::(CollaborationApi,AsHostEndpointWin.Microsoft.Rtc.Internal.Collaboration.ApplicationSharing.Media.IAsHostEndpoint.StopSession) Forcing STOPPED state omitted from plugin.StopSharing call
10/15/2013-09:20:09.015 0001TL_ERROR(UI)::(UI,Microsoft.OCG.ReachClient.AppShare.AppShareManager.OnAppShareConnected) Session connection failed, type=eSharerSession"


When the LYNC user (with NO LYNC client) joined LYNC Meeting through LYNC WebApp as Guest, the desktop sharing as well as application sharing worked fine.

As we need to continue using OCS client for most of the LYNC users ( about 70%), we need to resolve this issue. Any solution for this is much appreciated.

Thanks in ad