To uninstall Linotype FontExplorer X, you have to delete the following files/folders besides the application itself:

• The preferences file: <user>/Library/Preferences/com.linotype.FontExplorerX.plist
• All installed Font-Request Plug-Ins: Located in the Plug-Ins folder of Adobe InDesign CS/CS2, Adobe Illustrator CS/CS2 or QuarkXPress 6.5/7.0.
• The Application Support folder:<user>/Library/Application Support/Linotype/FontExplorer X/
• Spotlight MetaData files:<user>/Library/Caches/Metadata/FontExplorer X/
• Spotlight Plug-In:<user>/Library/Spotlight/FontMDI.mdimporter