In a Vdi Environment the first time a user start a pairing operation, he need to sign-in again. This is normal and made by design. The following picture display this operation. It means therefore that the thin client should be able to join the Lync server and approve the Cert authority which delivered the Lync Server Certificate.
If it is the case and if the DVC channel is ok, then the client is invited to enter his credential and by clicking on the check box to memorize his credential, he will never had to do this again.
That’s great, but we have discovered that if the VM is Pooled (see Citrix definition below) When the user disconnect to the VM and reconnect to, by default, an another VM, he needs to sign in twice (One for Lync , one for the VDI plug in) . If the user use a dedicate VM this behavior do not occur. It means that the VDI plug in store probably his credential locally. All the users concerned by this behavior, have a random user profile which is downloaded from a central file service repository when the logon process occur.
The great question is: how to find a workaround and to avoid that each time the user logoff he need to resign in;-)
Pooled VM definition : Pooled machines provide desktops that are allocated to users on a per-session, first-come first-served basis. Pooled-random machines are arbitrarily assigned to users at each logon and returned to the pool when they log off. Machines returned to the pool are available for other users to connect to. Alternatively, with pooled-static machines, users are assigned a specific machine from the pool when they first log on to XenDesktop. Users are connected to the same machines for all subsequent sessions. This allows users of pooled-static machines to be associated with specific VMs, which is a licensing requirement for some applications. Pooled desktops are freshly created from the master VM when users log on, although profile management can be used to apply users’ personal settings to their desktops and applications. Any changes that users make to their desktops are stored for the duration of the session, but are discarded when users log off. Maintaining a single master VM in the data center dramatically reduces the time and effort required to update and upgrade users’ desktops.