Component Based Servicing Log
The Component-Based Servicing Log can be helpful if you get a message like this in your Installation log:
MSI (s) (44:14) : Assembly Error (sxs): To get more diagnostic information, enable the Component Based Servicing Log.
The Component Based Servicing Log is located in %windir%\logs\cbs\cbs.log (C:\Windows\Logs\CBS)
To get the cbs log you may first need to set:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Component Based Servicing EnableLog=dword:00000001
Windows Installer SDK Tools
Wilogutl.exe assists the analysis of log files from a Windows Installer installation, and it displays suggested solutions to errors that are found in a log file. You can use it to debug installation, repair and removal of a product.
For more information go to http://msdn2.microsoft.com/en-us/library/aa372811.aspx.