$ desktop-file-validate claws-mail.desktop claws-mail.desktop: error: (will be fatal in the future): value "Email" in key "Categories" in group "Desktop Entry" requires another category to be present among the following categories: Office;Network Present in current CVS head, too. I propose adding Office.
Changes related to this bug have been committed. Please check latest CVS and update the bug accordingly. You can also get the patch from: http://www.claws-mail.org/tracker/ 2012-10-18 [mones] 3.8.1cvs101 * claws-mail.desktop Fix bug #2761 and remove invalid GTK main category
/usr/share/applications/claws-mail.desktop: hint: value "Network;Office;Email;" for key "Categories" in group "Desktop Entry" contains more than one main category; application might appear more than once in the application menu
Sorry, but that's not even the same bug, it's just a hint.