diff --git a/headers/os/support/Errors.h b/headers/os/support/Errors.h
index 7f063bb472..993cfbb01d 100644
--- a/headers/os/support/Errors.h
+++ b/headers/os/support/Errors.h
@@ -55,6 +55,7 @@ enum {
 	B_BUSY,
 	B_NOT_ALLOWED,
 	B_BAD_DATA,
+	B_DONT_DO_THAT,
 
 	B_ERROR = -1,
 	B_OK = 0,