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Problem

You change the account of the administration server service via the klsrvswch tool. Note that this is the only way to change the account, manual modification (for example, via services.msc) is not supported. 

Then, the you run the Install required updates and fix vulnerabilities task.

As a result, the task is cancelled and updates are not installed. 

Diagnostics

The following error can be found in $klserver-1093.log:

20.11.2023 10:26:16.683 00000ADC.000028C0 L4  KLSTD: Error 0x5 accessing the file 'C:\ProgramData\KasperskyLab\adminkit\1093\.working\FTServer\#WSUS#', m_dwWin32Access=0x80000000, m_dwWin32Creation=0x3, m_dwWin32Flags=0x8000000

20.11.2023 10:26:16.683 00000ADC.000028C0 L1  KLSTD: Error ERROR_ACCESS_DENIED (attempt 186 from 300) for the file 'C:\ProgramData\KasperskyLab\adminkit\1093\.working\FTServer\#WSUS#'

When checking permissions of the file C:\ProgramData\KasperskyLab\adminkit\1093\.working\FTServer\#WSUS#, it lacks the new service account assigned to the kladminserver service:

In this example, the Administration Server account is the old service account used to start the KSC service. 

Workaround

Add the new KSC Service account or the KLAdmins group to the access control list of the #WSUS# file and grant it full access: