Rick, We do use QOS and I will have the comm. Folks take a look!! Like always, you are probably right on the money!!! Thanks. Jay TCS Field Systems-La Crosse Citrix Server Team ________________________________ From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Rick Mack Sent: Friday, July 20, 2007 2:24 PM To: thin@xxxxxxxxxxxxx Subject: [THIN] Re: Protocol Driver Error Hi Jay, If you're using any sort of QOS on your network, chances are good that QOS optimization is set for ICA (port 1494) instead of session reliability (port 2598). So if your comms people have set everything up for ICA prorocol prioritization followed by SMB etc, guess what gets the lowest priority of all, ICA over port 2598. This can cause timeout errors and a bunch of other connection issues. You've got 2 possible fixes if QOS is the culprit. Make sure your comms guys realize you're using ICA over port 2598 and get them to set up QOS etc appropriately or turn off session reliability. If your comms links are reliable, nobody will notice and ICA will get the proprity it needs. regards, Rick -- Ulrich Mack www.commander.com From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Jensen, Jay Sent: Friday, July 20, 2007 2:05 PM To: THIN@xxxxxxxxxxxxx Subject: [THIN] Protocol Driver Error We use session reliability on our Secure Gateway environment which runs with Web Interface Version 3.0 and Windows 2003 server. We have been getting too many Protocol Driver errors using the PS 4.0 Client 9.23. We have tried PS 4.0 Client 10.0 and that has the same issue. Looking at this error on Citrix Web Site / Google, none of the errors seem to fit our environment. Our PS 4.0 Servers are running a mix of PS 4.0 Roll-up 2 and 3 and it is happening on both Roll up versions. We also are using Windows 2000 Terminal Server.