diff --git a/xpinstall/res/locale/en-US/xpinstall.properties b/xpinstall/res/locale/en-US/xpinstall.properties
index 3969c18b9d11..9d07d23bb62b 100644
--- a/xpinstall/res/locale/en-US/xpinstall.properties
+++ b/xpinstall/res/locale/en-US/xpinstall.properties
@@ -49,7 +49,7 @@ RenameFolder=Rename Folder: %s to %s
 WindowsShortcut=Windows Shortcut: %s
 MacAlias=Mac Alias: %s
 WindowsRegisterServer=Windows Register Server: %s
-UnknownFileOpCommand=Unkown file operation command!
+UnknownFileOpCommand=Unknown file operation command!
 
 Patch=Patching: %s