Windows Guest Additions

Note: All following modifications need Administrator rights in the guest VM! Also, the directory C:\Temp must exist on the guest.

Open the registry editor (regedit.exe) and add the key:

HKLM\SYSTEM\CurrentControlSet\Services\VBoxGuest\LoggingEnabled = 0xFF (REG_DWORD)

There currently is no common / generic way of enabling logging for all guest-side components, e.g. for the auto-logon components (VBoxGINA and VBoxCredProv) there are registry keys which must be used in conjunction with the key above:

Auto-Logon (Windows)

HKLM\SOFTWARE\Oracle\VirtualBox Guest Additions\AutoLogon\LoggingEnabled = 0xFF (REG_DWORD)
HKLM\SOFTWARE\Oracle\VirtualBox Guest Additions\AutoLogon\LoggingLevel = 0xFF (REG_DWORD)

VBoxTray

At the moment only an instrumented (debug) build will help here.

VBoxService

HKLM\SYSTEM\CurrentControlSet\Services\VBoxService\ImagePath = "system32\VBoxService.exe -vvvv --logfile c:\Temp\VBoxService.log" (REG_EXPAND_SZ)

Miscellaneous

For the other components (like Shared Folders) it should be sufficient to enable the guest driver registry key in order to let through the guest's debug logging into the VBox.log on the host.

Note: The host limits the number of guest log entries by default (per log group). To enable unlimited logging of all components the host environment variable

VBOX_RELEASE_LOG="-all.restrict"

must be set. Otherwise we have a limit of 32k entries per logging group.