On a Windows Server 2012-based computer that has the Remote Desktop Services (RDS) role installed, the following issues occur.
Assume that you have the Remote Desktop Services (RDS) role installed on a computer that is running Windows Server 2012. You run an application that uses Windows Terminal Server virtual channel APIs (such as the WtsVirtualChannelOpen and WtsVirtualChannelClose APIs) to create and use virtual channels in a Remote Desktop Protocol (RDP) session. In this situation, RDP static virtual channels do not work. Additionally, Virtual channel communication fails in the RDP session if you do not reestablish the connection.
This issue does not affect other running RDP sessions.
This issue can appear in different ways. For example, when you schedule several print jobs in a Remote Desktop Protocol session, the print jobs are deleted.
Consider the following scenario:
You have the Remote Desktop Services (RDS) role installed on a Windows Server 2012-based computer.
You run an application that uses Windows Terminal Server virtual channel APIs (such as the WtsVirtualChannelOpen and WtsVirtualChannelClose APIs) to create and use virtual channels in a Remote Desktop Protocol (RDP) session.
The application tries to open a static virtual channel by using a channel name that does not exist.
In this scenario, the operation that opens the static virtual channel stalls for 10 seconds when the system tries to open the nonexistent virtual channel again.
Cause of Issue 1
This issue occurs because of a race condition that occurs when the system cannot open a static virtual channel.
Cause of Issue 2
This issue occurs because the channel is not closed when the channel receives an error when the virtual channel is created.
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.
If the hotfix is available for download, there is a "Hotfix Download Available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft website:
Note The "Hotfix Download Available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.
To apply this hotfix, you must be running Windows Server 2012.
To apply this hotfix, you do not have to make any changes to the registry.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows Server 2012 file information notes
Important Windows 8 hotfixes and Windows Server 2012 hotfixes are included in the same packages. However, only "Windows 8" is listed on the Hotfix Request page. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 8" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
6.2.920 0.16 xxx
Windows Server 2012
6.2.920 0.20 xxx
Windows Server 2012
GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2012" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintain the state of the updated components. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x64-based versions of Windows Server 2012
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about the static virtual channel, go to the following Microsoft website: