Recently I have been involved in a Citrix project roll out. I have found significant issues with the Citrix NetScaler’s VPX HA flapping, which was in turn causing user disconnections. After much digging, I managed to find that this was due to a bug (BUG0456218) on the NetScaler’s. http://support.citrix.com/article/CTX201524 This occurs when AppFlow Logging is enabled on NetScaler Gateway virtual server, NetScaler failover causes ICA sessions to disconnect. As soon as I turned AppFlow off. I found that users were a lot more stable and were less affected by Failovers. I also set High Availability Status to ‘Stay Primary’. Hopefully this will be resolved in a patch release soon.