<p>During our Citrix v7.12 LTSR environment update with CU4, we were unable to update one of our VDA servers with the following error message:</p>
<p>Installation failed. The following components failed to install. Virtual Delivery Agent. Failed.</p>
<p><img class="alignnone size-full wp-image-4663" src="https://www.wincert.net/wp-content/uploads/2022/06/vda-upgrade-error-2.jpg" alt="" width="581" height="264" /></p>
<p>After checking the &#8220;Why did this fail?&#8221; link we could see that the problem was with the removal of <strong>MSI product &#8216;CitrixHDXMediaStreamForFlash-Serverinstall-x64.msi with code &#8216;InstallSourceAbsent&#8217; (1612)</strong>.</p>
<p><img class="alignnone size-full wp-image-4665" src="https://www.wincert.net/wp-content/uploads/2022/06/vda-upgrade-error.jpg" alt="" width="495" height="259" /></p>
<p>After that, I completely removed the Virtual Delivery Agent (VDA) from the server and installed a fresh LTSR v7.12 CU4 update on the server. Once the installation was completed, we noticed that we were getting a grey screen when trying to open the desktop session.</p>
<p>Once I&#8217;ve checked the Event Log I could see the following error message on this specific server:</p>
<p><strong>The Citrix Universal DLL Injection Driver has encountered an unexpected error.</strong></p>
<p><strong>Source CtxUvi</strong><br />
<strong>Event ID: 1005</strong><br />
<strong>Level: Error</strong></p>
<p>In order to solve this issue, run the Registry Editor on the VDA with the error and navigate to the following handle to the registry key:</p>
<p><strong>HKLM\Software\WOW6432Node\Citrix\CtxHook\AppInit_DLLs\HDXMediaStreamforFlash</strong></p>
<p><img class="alignnone size-full wp-image-4667" src="https://www.wincert.net/wp-content/uploads/2022/06/vda-upgrade-error-3.jpg" alt="" width="766" height="323" /></p>
<p>Right-click on the <strong>HDXMediaStreamForFlash</strong> key and click <strong>Delete</strong>. Restart the server afterward. It should be working now.</p>
<p>It&#8217;s worth saying that we have successfully upgraded a large number of VDAs, but this one had to be reinstalled with the VDA agent and Citrix Workspace. Even though there was no issue adding Delivery Controllers for this VDA, a fresh installation of the LTSR 7.12 CU4 version performs differently than an update.</p>
<p>Comments are welcome!</p>

Grey Screen on VDAs Server Desktop after 7.12 LTSR update to CU4
