My first Citrix bug of the year!

Posted: January 22, 2014 in Citrix
Tags: , , , , , ,

As many of my coworkers and former coworkers know, I have a strange, unintended ability to locate bugs in software.  Today’s bug was the first serious bug of the year.

Over the course of the past several months, I had been working with Citrix Escalation on a different bug.  Apparently we were one of the 5 companies in the world to experience this particular bug.  (Null pointer dereference in the audio module vdcamn.dll that would seemingly randomly disconnect ICA sessions.  But, I had some private fix files, and those files became part of Receiver 3.4 Enterprise CU3).

This holiday weekend was our normal patch weekend, and I had a long string of items to patch, including upgrading my PVS 6.1 to Hotfix#19.  As some will know, HF19 is a complete reinstall, including the old fun task of reverse imaging your vdisks to replace the target software etc.  During the course of this imaging, I had a different problem that I was working on (at least I thought it was.  I ended up restarting the imaging process, because I was sure I had broken *something*.  During the course of a VDA uninstall, I kept getting strange errors about personal vDisk not being able to be installed in the XenDesktop setup log (%temp%\Citrix\XenDesktop Installer\XenDesktop installation.log) with an error 1603.  I completely redid my reverse image on the broken disk, and started again.

As I hammered away at this process, I had the issue creep up again.  Since it seemed very odd that the same error would reappear, when I was following the process correctly, I started digging in deeper.  When I started looking around the file systems, I noticed on the one disk image that there were leftovers for personal vDisk in c:\program files\citrix, and in c:\program files (x86)\Citrix, so I suspected I might have found my issue.  I cleaned them up and tried the installation again, and……   same error.

I poked around ye ole’ internet again, and found a very helpful article –  It mentioned getting more information in the MSI logs.  However, it also mentioned that many products won’t produce MSI logs even using his listed methods.  It was still worth a look.  Fortunately, Citrix provides the MSI logs in a subdirectory – %temp%\Citrix\XenDesktop Installer\MSI Log Files\).  There I found read errors when accessing my iso file in VMWare.

All of my standalone machines registered correctly, but none of my PVS machines would register.  That was odd..  It’d been a very long day so I just called Citrix, since I was already on my well to a nice brain-fry.  We started digging around looking at the basics.. I explained my various steps, and what was occuring.  So, we pulled out my trusty copy of XDPing ( and it was showing failures in the DDC registration, like it could not find the DDCs.  We jumped immediately into the registry (although the Citrix tech started at the top of the tree to search, I pulled up the article listing the value (  The registry value for ListOfDDCs was missing.  I inserted the appropriate value in place, restarted the Citrix Desktop Service, and within 3 seconds it was registered.

With that information in hand, I let Citrix go while I worked on reinstalling my vDisks.  I rebuilt them all, however, they all had issues uninstalling the VDA – all the errors pointed to references of the personal vDisk installer on the iso image.  (At this point, I still do not know if I have a VMWare problem, or a corrupted iso image).  I installed the 5.5 VDA and set the registry value.  I upgraded the VDA with the hotfix (XD560VDAWX64400 – (The 32bit version is I didn’t bother with the sealing steps, this was just a quick test.  I brought the image back online, and it would not register.   Back to the registry, and the ListOfDDCs value was gone. I put the image back in private mode, reinserted the ListOfDDCs, put it back in standard, and retested again; success!.

I emailed a few people at Citrix, and I was told this is normal behavior when upgrading the 5.5 VDA.  I let them know what it happened with the 5.6 VDA also.  So, it’s a bug.   But, I have no idea why they would deliberately strip out the ListOfDDCs?

David F.


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