Index: /trunk/include/VBox/HostServices/GuestPropertySvc.h
===================================================================
--- /trunk/include/VBox/HostServices/GuestPropertySvc.h	(revision 75991)
+++ /trunk/include/VBox/HostServices/GuestPropertySvc.h	(revision 75992)
@@ -35,14 +35,16 @@
 
 
-/** Maximum length for property names */
+/** Maximum length for property names. */
 #define GUEST_PROP_MAX_NAME_LEN             64
-/** Maximum length for property values */
+/** Maximum length for property values. */
 #define GUEST_PROP_MAX_VALUE_LEN            128
-/** Maximum number of properties per guest */
+/** Maximum number of properties per guest. */
 #define GUEST_PROP_MAX_PROPS                256
-/** Maximum size for enumeration patterns */
+/** Maximum size for enumeration patterns. */
 #define GUEST_PROP_MAX_PATTERN_LEN          1024
-/** Maximum number of changes we remember for guest notifications */
+/** Maximum number of changes we remember for guest notifications. */
 #define GUEST_PROP_MAX_GUEST_NOTIFICATIONS  256
+/** Maximum number of current pending waits per client. */
+#define GUEST_PROP_MAX_GUEST_CONCURRENT_WAITS 16
 
 
Index: /trunk/src/VBox/HostServices/GuestProperties/service.cpp
===================================================================
--- /trunk/src/VBox/HostServices/GuestProperties/service.cpp	(revision 75991)
+++ /trunk/src/VBox/HostServices/GuestProperties/service.cpp	(revision 75992)
@@ -1190,10 +1190,10 @@
                             it = mGuestWaiters.erase(it);
                         }
-                        //else if (mpHelpers->pfnIsCallCancelled(it->mHandle))
-                        //{
-                        //    /* Cleanup cancelled request. */
-                        //    mpHelpers->pfnCallComplete(it->mHandle, VERR_INTERRUPTED);
-                        //    it = mGuestWaiters.erase(it);
-                        //}
+                        else if (mpHelpers->pfnIsCallCancelled(it->mHandle))
+                        {
+                            /* Cleanup cancelled request. */
+                            mpHelpers->pfnCallComplete(it->mHandle, VERR_INTERRUPTED);
+                            it = mGuestWaiters.erase(it);
+                        }
                         else
                         {
@@ -1207,5 +1207,5 @@
                 }
 
-                //if (cPendingWaits < 16)
+                if (cPendingWaits < GUEST_PROP_MAX_GUEST_CONCURRENT_WAITS)
                 {
                     try
@@ -1220,9 +1220,9 @@
                     }
                 }
-                //else
-                //{
-                //    LogFunc(("Too many pending waits already!\n"));
-                //    rc = VERR_OUT_OF_RESOURCES;
-                //}
+                else
+                {
+                    LogFunc(("Too many pending waits already!\n"));
+                    rc = VERR_OUT_OF_RESOURCES;
+                }
             }
             /*