KB484351: MicroStrategy Narrowcast Services fail with segmentation errors, generating a core file for process MCSBMRT.exe

Description 

The Narrowcast Services will fail to deliver as scheduled with a crash on the Subscription Book process. This is a very uncommon scenario that only happens when different Narrowcast Services (e.g. Distribution Manager, Execution Engine, Logging Client/Server/Consumer) are run using different user accounts.
This causes 2 or more services to fail communicating with each other because of their different privileges at the OS level, causing the system to crash. This has only been observed in Windows 2012 R2. 
Should you experience similar segmentation issues but are not using different user accounts to run your Narrowcast Services, please refer to these other KB articles:

• KB482967: MicroStrategy Narrowcast services fail with segmentation errors: Segmentation failed [Subscription Set ID: BB3AE395F67E4A9E9BE2BD50E80C9195]
• KB439853: MicroStrategy Narrowcast services fail with segmentation errors: “Unable to close the Subscription Book” “Segmentation failed” “Service execution finished with error”

Symptoms

• Narrowcast Services will fail to deliver
• A small core file for the

  MCSBMRT.exe

  process will be generated and/or the following error
  

  Error,4/21/2020 5:42:35 AM,Application Error,1000,(100),"Faulting application name: MCSBMRT.EXE, version: 11.2.0.28349, time stamp: 0x5de9f3d1

  
  
• Leftover files will appear under:

  [Narrowcast Install path]\Narrowcast Server\Delivery Engine\

  
  narrow_1
  
• An error similar to the following will be displayed in the DELogs.log:
  

  [MACHINENAME::DM]:2968:[THR:0x2BE4][04/21/2020 05:42:37.030][Level:Info (DM)][Code:0x00000970]Unable to close the Subscription Book [MACHINENAME::DM]:2968:[THR:0x2BE4][04/21/2020 05:42:37.046][Level:Moderate Error][Code:0x00000A98]Service ID [DDCD3B03317844BD9F275872C87E41D7] Execution ID [7D569E9061264A51A3AD954EA799A998] Segment ID [........]Segmentation failed [Subscription Set ID: 94D79E2B5EBE4C39BC3BED12B63EC429]

  
  

Why is this happening?

Starting with Window Update (KB4467703) for Windows 2012 R2, Windows added a limitation to their Visual Basic code that prevents Narrowcast processes to successfully communicate between each other. In order to address this Windows limitation, Narrowcast 2020 is enabled the capacity to use temporary files for the correct communication between the required processes.
In the very specific Narrowcast configuration where the different Services are running under different accounts (e.g. Delivery Engine with admin1, Execution Engine with admin2, Logging Services with admin3), the spawned temporary files may not be visible across the different processes should the users running the service do not share privileges to see each other’s files or save the files to different folders (operative system level limitation). This causes the processes to fail to communicate with each other and therefore end up crashing.

Solution

Narrowcast 2020 comes with a new registry key that stores the location of a common temp folder for all NCS services to store their communication temporary files, if needed. Should this key does not exist, it should be created.

• Key name: "

  Log File Path

  "
• Registry Path: "

  \HKEY_LOCAL_MACHINE\SOFTWARE\MicroStrategy\Strategy Broadcast Server\7.0\Distributed Logging Service\LoggingConsumer\

This key value is suggested to be set to the same path as the

MCSBMRT.exe

and

MCDM.exe

executables, usually at: “

[Narrowcast Install path]\Narrowcast Server\Delivery Engine\

”. If possible, it is also suggested to run all Narrowcast Services under the same user account.
*Note: Please note the “\” at the end of the path string.
After setting the value for the above registry key, restarting all Narrowcast services is required.
If the step above is done correctly, the temporary files will be created by the sender process and deleted once consumed by the receiver process. No leftover files will remain. Should any leftover files remain from before the key was created, they can be safely deleted.