To restore the factory or installation settings of ARES Commander you can rename or remove the following user settings folder under:
Further you should delete the two com.graebert.ares-commander-edition.plist and com.graebert-gmbh_ares-commander-edition.drawing.plist-files in the\Users\[User name]\Library\Preferences\.
The folder \Users\[User name]\Library is probably hidden, so you may have to change your view settings or use the "Go to Folder..." option of the Finder's Go pull-down menu.
In the first versions of ARES Commander (before 2012.2.49) the local user folder and the plists were named in capital letters with space characters (e.g. ARES Commander Edition).
The ARES Commander application should be closed during the process