Note: The following applies if your ownCloud server is running on Linux; it is not valid for an ownCloud server running under Windows; on Windows there is another problems with special characters which unfortunately can’t be solved at the moment because it’s a php problem (see this discussion).
If special characters in filenames you have uploaded to ownCloud (be it via the client or via the web interface) don’t show up properly (e.g. that a special character at the beginning just disappears in the web interface), try this:
Check the locale installed:
If “en_US.UTF-8” is not on the list shown as output of this command, run one of these command to install it:
See also this thread: http://forum.owncloud.org/viewtopic.php?f=3&t=8004.
In case you are using PHP via FastCGI, be sure to check this thread: https://forum.owncloud.org/viewtopic.php?p=63964#p63964