I have one development server with SharePoint 2010 installed. Everything works fine except when I try to access the site collection through Citrix none of the ribbon functionality works. It just freezes up. It appears that only Ajax related functionality is being affected. I ran a trace and found that the citrix call included a call to /_vti_bin/diagnostics.asmx which creates the following record in the windows event viewer: Fault bucket , type 0 Event Name: ULSClientScriptException14 Response: Not available Cab Id: 0 Problem signature: P1: UNKNOWN P2: 14.0.4762.0 P3: MISSING P4: Invalid_character P5: Microsoft_Internet_Explorer P6: 7 P7: MISSING P8: P9: P10: Attached files: These files may be available here: C:\ProgramData\Microsoft\Windows\WER\ReportQueue\Critical_UNKNOWN_1920b9b17edb8184f3539b69aebe69548a29751d_140c2a30 Analysis symbol: Rechecking for solution: 0 Report Id: 1367319f-6a2b-11e0-95c0-0050568d309b Report Status: 4 That directory contains a file with the following content: Version=1 EventType=ULSClientScriptException14 EventTime=129476530072841475 ReportType=1 Consent=1 ReportIdentifier=1367319f-6a2b-11e0-95c0-0050568d309b Response.type=4 Sig[0].Name=Problem Signature 01 Sig[0].Value=UNKNOWN Sig[1].Name=Problem Signature 02 Sig[1].Value=14.0.4762.0 Sig[2].Name=Problem Signature 03 Sig[2].Value=MISSING Sig[3].Name=Problem Signature 04 Sig[3].Value=Invalid_character Sig[4].Name=Problem Signature 05 Sig[4].Value=Microsoft_Internet_Explorer Sig[5].Name=Problem Signature 06 Sig[5].Value=7 Sig[6].Name=Problem Signature 07 Sig[6].Value=MISSING DynamicSig[1].Name=OS Version DynamicSig[1].Value=6.1.7600.2.0.0.272.7 DynamicSig[2].Name=Locale ID DynamicSig[2].Value=5129 FriendlyEventName=ULSClientScriptException14 ConsentKey=ULSClientScriptException14 AppName=IIS Worker Process AppPath=C:\Windows\System32\inetsrv\w3wp.exe Does anybody have experience with such an error? Thanks! Peter Arblaster