LyncBackupService.exe stops responding after pool pairing Skype for Business Server 2019

• Applies to:

  Skype for Business 2019

Symptoms

You receive Event ID 4007 and LyncBackupservice.exe stops responding after enabling pool pairing for two pools on a Skype for Business Server 2019. The following details appear in the log:

     Log Name:      Lync Server
Source:        LS Backup Service
Date:          xx/xx/xxxx xx:xx:xx
Event ID:      4007
Task Category: (4000)
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      FE1.contoso.com
Description:
An unhandled exception was encountered.

Exception Details. System.NullReferenceException: Object reference not set to an instance of an object.
   at Microsoft.Rtc.BackupService.BackupModuleHandler..ctor(IBackupModule backupModule, Topology topology)
   at Microsoft.Rtc.BackupService.BackupModuleController.RefreshBackupModuleHandlers()

Cause

When enabling the pool pairing service for the first time, the Skype for Business server installs LyncBackupService.exe using RTM binaries whether or not the Skype for Business Server 2019 Cumulative Update has already been installed.

The Skype for Business Server 2019 Cumulative Updates include an update to the LyncBackupService. The crash occurs because of a mismatch between versions of Lyncbackupservice and the Skype for Business Server 2019 Core Components.

Resolution

To fix this issue, run the Skype for Business Server Cumulative Update installer again in order to patch the LyncBackupService to a version compatible with the Skype for Business Server 2019 Core Components.

More information

Front End pool disaster recovery in Skype for Business Server

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