How to enable logging for the .MSI host installer of VirtualBox

The following steps apply for the Windows version of VirtualBox.

1. Go to Start -> "Run ..."
2. Type in "regedit.exe" and press Enter
3. Navigate to the key "HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer" (Left pane). If the key itself doesn't exist, just create it.
4. In the right pane, right click and choose "New" -> "String value"
5. Name the value "Logging".
6. Double click on the new created "Logging" value and set the value to "voicewarmupx"
7. Close regedit.exe

After the above steps the VirtualBox host installer should produce a log starting with "MSI" in your temporary directory the next time you're starting the installer.

On 32-bit Windows, the temporary directory is usually located at "C:\Documents and Settings\<Your Username>\Local Settings\Temp\".
On 64-bit Windows, it's under "C:\Users\<Your Username>\AppData\Local\Temp".

Be sure you're picking the most recent one by sorting the files by date!