as the value to enable Windows Installer logging.

Windows includes a registry-activated logging service to help diagnose Windows Installer issues. This article describes how to enable this logging service.
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To enable Windows Installer logging yourself, open the registry by using Regedit.exe, and then create the following subkey and keys:

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer

Reg_SZ: Logging
Value: voicewarmupx  The letters in the value field can be in any order. Each letter turns on a different logging mode. Each letter’s actual function is as follows for MSI version 1.1:
– How to enable Windows Installer logging (KB223300)