Visual Studio log file

From the documentation of the /Log command line switch:

If LogFile is not specified, two files
will be written to the current user’s
non-localized application data folder.
The non-localized application data
folder for Visual Studio can be found
from the APPDATA environment variable.
For example, for Visual Studio 2008,
the folder is
%APPDATA%\Microsoft\VisualStudio\9.0,
where %APPDATA% represents the value
in the APPDATA environment variable.

The two files are, by default, called
ActivityLog.xml and ActivityLog.xsl.
The former contains the activity log
data and the latter is an XML style
sheet which provides a more convenient
way to view the XML file. To view the
Activity log in your default XML
viewer (e.g. Internet Explorer)

You will probably have to run devenv with the /Log switch for these files to be created. Visual Studio doesn’t seem to log anything by default.