Carl, Thanks for the suggestions. I have disabled API Hooks per the instructions in the Citrix article and have disabled SpeedScreen Browser Acceleration. The problem still occurs. Using Sysinternal's LISTDLLS.EXE on the process that is crashing, I notice that the application HAS the mfaphook.dll loaded, but none of the associated hook dlls listed under the CTXHook section in the registry, so it appears that the disabling the API Hooks for the application was successful in that it did not load any of the associated hook DLLs. Perhaps I should try applying the MF Rollup 2 ? Regards, Rob _____ From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Carl Stalhood Sent: Monday, February 06, 2006 9:13 PM To: thin@xxxxxxxxxxxxx Subject: [THIN] Re: Application Memory Error When Using ICA Try this and see if it works: Disabling Citrix API Hooks on a Per Application Basis http://support.citrix.com/article/CTX107825&searchID=14841441 Also, try turning off SpeedScreen Browser Acceleration _____ From: thin-bounce@xxxxxxxxxxxxx [mailto:thin-bounce@xxxxxxxxxxxxx] On Behalf Of Armstrong, Robert Sent: Monday, February 06, 2006 3:36 PM To: Thin@xxxxxxxxxxxxx Subject: [THIN] Application Memory Error When Using ICA Greetings, I have an application that produces a memory error when accessed via ICA (seamless published application and remote desktop). The application, when run from the console of the Citrix Server does NOT produce the memory error. Likewise, when I remote desktop through RDP to the same server, the error does not occur. The error message is: The instruction at 0X77f88216 referenced memory at 0x00000010. The memory could not be written. Following the error, the application crashes and the process is no longer in the process list. I'm running MF XPe FR3 on Windows 2000 Server SP4. I have tried ICA Clients v6 through v8 and all produce the error. Does anybody have any suggestions on how to troubleshoot this problem or why it only occurs when using ICA? Please let me know if you need more information. Thank you, Rob _____ This message may contain confidential and/or privileged information. If you are not the intended recipient or authorized to receive this for the intended recipient, you must not use, copy, disclose or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by sending a reply e-mail and delete this message. Thank you for your cooperation. _____ This message may contain confidential and/or privileged information. If you are not the intended recipient or authorized to receive this for the intended recipient, you must not use, copy, disclose or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by sending a reply e-mail and delete this message. Thank you for your cooperation.