Index: /trunk/src/VBox/Devices/Storage/DevAHCI.cpp
===================================================================
--- /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 51623)
+++ /trunk/src/VBox/Devices/Storage/DevAHCI.cpp	(revision 51624)
@@ -1279,4 +1279,6 @@
         }
     }
+    else /* Just update the value if there is no device attached. */
+        pAhciPort->regSCTL = u32Value;
 
     return VINF_SUCCESS;