Uniface crashing on HTML grid.

Author: mmontealegre@commandalkon.com (mmontealegre)

We are doing our first implementation using the HTML widget.  In citrix Uniface will sometimes crash when loading the HTML grid we are using.  The DLL that crashes is dhcpcsvc6.DLL.  After doing some googling it appears that adding Uniface.exe to the DEP (data execution prevention) exceptions.  Has anyone else had this experience?  Does anyone know why we need to add it to the DEP?


  1. Hello, I also did a quick search on the Internet and I've found the following posting on the madshi.net forum:

    "We see this issue quite regularly as we use MAPI and lots of our users run our application on TS.

    Office (and Outlook in particular) is not DEP safe on Windows 2008 R2. http://support.microsoft.com/kb/2028367

    If you're wondering why this doesn't occur on non-server versions of Windows (e.g. XP, Vista, Win7, etc.), it's because *only* 'system' processes run with DEP enabled by default in desktop versions, whereas DEP is enabled on *all* processes by default in server versions. TS (and Citrix) are the classic case where a server version of Windows ends up hosting desktop applications and thus where you see this annoying issue.

    Now in the above KB, Microsoft recommends exempting Outlook.exe from DEP to workaround the issue. However, when talking via MAPI to Outlook, the problematic non DEP-safe code will be running in *your* address space, thus you will need to exempt *your* processes exe from DEP checking or suffer these spurious AVs." I guess this also answers, why you need to add Uniface to the DEP. I hope this helps. Kind regards, Daniel

    Author: diseli (daniel.iseli@uniface.com)
  2. This problem has resurfaced in the last few months (the original post to this forum is from a coworker). Even though Uniface is in the DEP, the "show" statement on forms containing an HTML widget will sometimes crash the application, with the event viewer saying the crash came from dhcpcsvc6.dll. We have been able to identify a workaround, by forcing the application to start in Compatibility Mode for Windows XP Service Pack 3. Any idea what could be the real issue here or how to fix it rather than avoid it?

    Author: jgilbert (jgilbert@commandalkon.com)
  3. This issue is probably related to the problem described here. Since Uniface version 9.7.02 the DEP policy will be automatically enabled when the HTML widget is initialized. This means that the problem with the dhcpcsvc6.DLL can resurface again. You could also try to use the second workaround mentioned in the linked post (Disable IAT). But it's interesting to know that setting the Compatibility Mode to Windows XP Service Pack 3 also resolves this issue. Hope this helps. Kind regards, Daniel Iseli Uniface Technical Support

    Author: diseli (daniel.iseli@uniface.com)