Update: Further investigation reveals that the issue is not confined to Windows Client 4.0.1. There is no need to move (or benefit from moving) your users away from that release.
Problem Summary
With Windows Client, disconnecting or signing out from a Workspot desktop sometimes causes the desktop to hang, showing a black screen instead of the desktop. The same issue causes spontaneous connection drops (but without hanging), and a loss of performance.
Who is Affected
Workspot Windows Client users whose connections are handled by a Workspot Gateway Cluster (Managed Gateway).
Discussion
Workspot is working to resolve this problem.
A fix is expected in the second week of July.
The fix is expected to consist of an automatic update to the Workspot Gateway Agent.
Progress will be reported here.
Root Cause
Workspot Gateway Agent 2.1.0 restricted the list of acceptable ciphers. This was taken to the point where none of the ciphers usable by the RDP protocol's optional UDP stream were acceptable. This caused the UDP stream to fail in a way that caused the problem described above.
The same issue causes mid-session disconnects (but without the black screen or desktop hangs: reconnecting works as usual).
The lack of the UDP stream can also cause performance reductions that are detectable by demanding users.
Workspot Clients other than the Windows Client are not affected.
Workaround
Try closing the desktop window with the "X" icon at the top righthand corner of the window, then reconnect.
(Persistent desktops only.) If this fails, reboot the Workspot desktop from the Client, using the "reboot" icon.
If the "reboot" icon is not shown on the user's desktop, a Control administrator can enable it on the "Edit Pool" page ("Resources > VDI Pools > poolname > Edit").
Alternatively, a Control administrator can reboot the desktop manually.