PathPrefixExclude[]=url_alias1
PathPrefixExclude[]=url_alias2
...
This directive tells the system which subtrees' virtual URLs should be unaffected by the "PathPrefix" directive. To add a subtree, specify the auto-generated URL alias of the top node in the most prioritized language.
PathPrefixExclude[] PathPrefixExclude[]=Media PathPrefixExclude[]=Users ...
Assuming that the default configuration of URL aliases is used, this will tell the system not to add any hidden prefix to virtual URLs that point to user accounts and media content (everything located in the "Users" and "Media" folders). For example, a URL like "www.mysite.com/Media/Images/MyPic" will be handled "as is", regardless of what is specified in the "PathPrefix" directive.