Skype for Business and Windows Fast User Switching resulting Lync Call Quality and Call Drops Issue

Some of the issues with Lync/Skype for Business call quality and call drop can be due to an integration issue between “Lync / SfB” and “Windows Fast User Switching” functionality. On a shared machine (desktop/laptop) especially at the front desk (reception), Fast User Switching is an easy way for users to allow others to log on to the machine without logging off or closing programs such as Lync. When a user is logged on to a computer and has locked the computer and a new user logs in to the same computer by using “Switch User” functionality, the new user is having problems using Skype for Business client for any type of Audio calls. User Switching without closing/exiting SfB session means that on a single machine two users are signed-in on SfB clients at the same time. Lync and SfB client doesn’t support fast user switching.

Some of the end-users comments based on this issue are:

• I'm getting other people's calls; hear a dialing tone when answered but the call connects before deafening beeping noise.
• Present of dialing tune while on call, and after a few seconds an alarm would go off - which hurts ear so much!
• When making a call via Lync/SfB you can hear the person on the other end but also a dialing tone - as if two calls are happening at the same time
• If the user tries to do a PSTN call there is a constant dial tone in the background and the call will eventually terminate.
• If the user tries to join an A/V Conference, there is no audio and the conference call will end.
• Resolution
• If the first user logged on to the machine is not available to close Lync/SfB, ask the second user to restart the machine. The restart will kill all logged-in user sessions. After restart and sign-in, there will be only one Lync process on that machine.

It important that we inform/communicate to all users “especially users at front desk/ reception changing shifts” who are using a shared machine to log-out from the machine instead of using user switching functionality to avoid call quality and drop issue on reception response groups.

I think machines at the front desk/reception should be disabled for “switch user functionality” as fast user switching at the reception response group can result in a major incident.