msi Diagnostic logging

Windows Installer supports detailed logging as a powerful diagnostic tool. Logging can be enabled in the following ways:

* Command-line: If installing an MSI package from the command-line, the /L switch can be used to enable logging. For example, the following command installs Package.msi and outputs verbose logging to c:\Package.log:

msiexec /i Package.msi /l*v c:\Package.log

* Windows Registry: The following registry value can be used in Windows Server 2003, Vista, and XP to enable verbose logging:

Key: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows\Installer
Value Name: Logging
Type: REG_SZ
Data: voicewarmupx

* Local Policy The following local policy must be changed in Windows Server 2008. The above registry key is no longer used:

Start > Run and type mmc to open a blank management console.
File > Add/Remove Snap-In...
Local Computer Policy, Add, OK, OK
Expand Administrative Templates > Windows Components > Windows Installer
Select "Logging" choose the "Enabled" option box and type "voicewarmupx" without quotes

The resulting log is named MSI#####.log (where "#####" is a unique random identifier) and is placed in the user's Temp directory (the 'temp' directory location is per-user, and is pointed to by the environment variable %temp%).

* Group Policy: The following Group Policy setting can be used to manage logging on multiple systems:

Computer Configuration -> Administrative Templates -> Windows Components -> Windows Installer -> Logging.

* Windows Installer API: If installing an MSI package programmatically, the MsiEnableLog function call can be used to create a log file and set the logging level for the life of the calling process.

* MsiLogging property: Windows Installer 4.0 introduces the MsiLogging property, which can be set to a list of flags indicating what information to log. The flags are similar to the flags that can be added to the /L switch to msiexec.exe or to the Logging policy setting. If MsiLogging is used, the MsiLogFileLocation property will be set to the location of the log file.

Although verbose logs are very useful for diagnosing Windows Installer problems, they can be very long and difficult to read without practice. A quick way to find the location of a problem in the log is to open it in a text editor (such as Notepad) and search for the phrase "Return Value 3". This entry commonly appears in logs close to the point where a critical error has occurred. The Windows Installer SDK provides a tool called WiLogUtl, which parses and annotates Windows Installer log files.

To output debug information in the log file, pass "x" on the command line or add it to the Logging registry value. For example, the following command installs Package.msi and outputs debug, verbose logging to c:\Package.log:

msiexec /i Package.msi /l*vx c:\Package.log