Index: /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp
===================================================================
--- /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp	(revision 59871)
+++ /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp	(revision 59872)
@@ -1191,4 +1191,11 @@
                     else if (strKey == "hypercallinterface")
                         fGimHvHypercallIf = RT_BOOL(strVal.toUInt32());
+                    else
+                    {
+                        AssertMsgFailed(("Unrecognized Hyper-V debug option '%s'\n", strKey.c_str()));
+                        return VMR3SetError(pUVM, VERR_INVALID_PARAMETER, RT_SRC_POS,
+                                            N_("Unrecognized Hyper-V debug option '%s' in '%s'"), strKey.c_str(),
+                                            strDebugOptions.c_str());
+                    }
                 } while (uPos != com::Utf8Str::npos);