Do you have McAfee VirusScan 8.0 installed? If so do you have the GDI detection fix installed from MS? If both are yes, then that is your problem. No fix available as of yet. Bob Barrett FVSD#52 ________________________________ From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Jan Homan Sent: Thursday, November 25, 2004 10:15 AM To: thin@xxxxxxxxxxxxx Subject: [THIN] Error 6004 We see sometimes the following error message in the Event Viewer of a W2000/Citrix XP server. Error 6004: A driver packet received from the I/O subsystem was invalid. The data is the packet. Any idea what this message mean, where it comes from and how I can solve it. Thanks. Jan