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KCS RTF Covers not working anymore after installing the Microsoft 9th March 2021 security Patches


Question / Problem: 

A customer who is using Richtext (RTF) covers reports a problem that these covers are not used anymore since applying the Microsoft March 2021 security patches.
Normal, non-Richtext covers are not affected by the problem. The problem might be related to different modules using the RTF Cover functionality, e.g.

  • TCOSS does not include anymore RTF covers in FAX messages being sent out
  • KCS TCFW Client does not resolve the Image view correctly for a message which uses a RTF cover
  • IPPrinter does not include anymore the RTF cover when printing e.g. Delivery/Nondelivery notifications using RTF covers

How can I recognize if the customer has this issue, but did not yet notice that problem?

In case of viewing a message with a linked RTF cover with the KCS TCFW Client, you will see the following trace line within the TCCP Trace file, when you switch the view from Text- to Image mode. You will also find an Event log entry with Event ID 1706 reported in the Windows Application event log.

[TCFW] ID:1706 The Rich Text conversion failed to produce TCI code - internal error code: 130. Please check the memory status of the system and the Rich Text for consistency. Additional information can be found in the trace file.

In case of using TCOSS you might see following Trace entries within the TCOSS trace files and also here you should find an event log entry with ID 1706 in the Application event log:

24/11:41:03.224 (1bf0/2370) TCRtf: Error -           CVP #10001, Thread 3912 ID: 9072 failed to select FAX bitmap into FAXDC, WinError: 0
24/11:41:03.224 (1bf0/20f0) TCRtf: Error -           CVP #10001 GetTCI exits because of invalid state 6 while waiting for conversion thread
24/11:41:03.225 (1bf0/20f0) ID:1706 The Rich Text conversion failed to produce TCI code - internal error code: 130. Please check the memory status of the system and the Rich Text for consistency. Additional information can be found in the trace file.

Answer / Solution: 

For resolving RTF covers, KCS uses the C:\TOPCALL\SHARED\TCRTF.DLL and Microsoft's C:\Windows\SYSWOW64\riched20.dll.
Additionally the device context of the TOPCALL FAX to TCRTF printer is used for rendering the RTF cover. A printer specific security
issue, which was addressed by Microsoft March 2021 patches is the reason so that RTF covers cannot be resolved anymore.

The vulnerability addressed by Microsoft is explained in this vulnerability report:

You will also find some more information about the issues fixed within the section Improvements and Fixes of this Microsoft article:


How can I find out for my specific operating system, which Microsoft Patch resolves this vulnerability and therefore causes problems with RTF covers?

The section Security Updates of the vulnerabilty report linked above gives you a list of Microsoft KB patches, which solve this issue and which might also cause the 
problems with KCS Richtext (RTF) covers, these are:

  • Microsoft Patch KB5000822 for Windows Server 2019
  • Microsoft Patch KB5000803 for Windows Server 2016
  • Microsoft Patches KB5000847/ KB5000840 for Windows Server 2012 R2

but also Client operating systems might be affected by this problem, e.g.

  • Microsoft Patch KB5000802 for Windows 10 20H2


How can I check if my KCS system has installed any of these patches, which cause the problems with RTF covers:

You will get a list of installed patches and the date when these patches have been installed by entering the command listed below
within a cmd prompt or powershell window. Check if the date when the customer first reported the problem with RTF covers matches
the installation date of the related patch:

wmic qfe list

Alternatively you might use the following Powershell command to view the installed Microsoft patches:


How can I resolve the issue of non-working RTF covers caused by these Microsoft patches released on 9th of March 2021?

Microsoft has released new patches for Windows Server 2016, 2019 and Windows 10 on 15th and 18th of March 2021, which replace the old patches
The following link contains a table of related patches, scroll down to the header line Overview of the March updates

  • Microsoft patch KB5000822 for Windows Server 2019 (released 9th March) has been replaced by KB5001638 (released 18th March)
  • Microsoft patch KB5000803 for Windows Server 2016 (released 9th March) has been replaced by KB5001633 (released 18th March)
  • Microsoft patch KB5000802 for Windows 10 20 H2 (released 9th March) has been replaced by KB5001649 (released 18th March)

Please check for latest Windows updates release on 18th of March directly on the Microsoft servers or download the corresponding patches
from the Microsoft Update catalog available here:
As far as we could see was the KB5001633 not available via Windows updates and it was necessary to install it manually.

What can I do if the customer is afraid of installing these new Patches or what can I do if no replacement patch is available?

Alternatively you might temporarily uninstall the corresponding patch (released on 9th March, 2021) using the following command

wusa /uninstall /KB:xxxxxxx   where xxxxxxx is the corresponding KB number without the "KB", e.g. 5000822

After uninstalling the Microsoft patch you will be prompted to reboot the server.
You can also uninstall the corresponding KB Patch by starting Control panel - Programs and Features - View installed updates.
Locate the Microsoft patch within the section Microsoft Windows and select then the Uninstall option from the right click context menu.

We got already confirmation from customer's that uninstalling the appropriate Microsoft patch or replacing the patch by the corresponding
successor patch solved their RTF cover issues.

Applies to:  

Product Version
KCS modules using RTF cover functionality (TCOSS, KCS Client, IPPrinter) Any, issue reported for KCS 10.3, Microsoft Patches shipped on 9th March 2021