Open the options, and expand the + on the left.
Profiles, click the Reset Profile button.
That may be per character, or per account I am not sure, but it will at least prove whether or not that is an issue with the settings, or something else intefering.
Either that or log out from the game completely (to the desktop), then enter the WTF\Account\YOUR_ACCOUNT\SavedVariables folder in your WoW directory, and delete the SexyMap.lua and SexyMap.lua.bak files.
UI & AddOns expert | Interface & Macros moderator - My work