I have Visual Studio 2005 set up to use Microsoft\'s symbol servers. I also have UltraMon installed, which injects a hook DLL into every process. Whenever I start debugging
You can also set up symbol server exclusions which will not be attempted to download in HKEY_CURRENT_USER\Software\Microsoft\Symbol Server\Exclusions or possibly also HKEY_LOCAL_MACHINE\Software\Microsoft\Symbol Server\Exclusions or via a .ini file at %WINDIR%\system32\inetsrv\Symsrv.ini (use the header [exclusions] and put each exclusion on its own line). The exclusions are simple pattern matches, so use msxml5.* for example.
In Visual Studio 2013 Pro, if the Microsoft Symbol Server is checked, VS will attempt to load all symbols on their server, causing a lot of extra time.