Index: /trunk/src/VBox/HostServices/GuestControl/service.cpp
===================================================================
--- /trunk/src/VBox/HostServices/GuestControl/service.cpp	(revision 35034)
+++ /trunk/src/VBox/HostServices/GuestControl/service.cpp	(revision 35035)
@@ -171,5 +171,5 @@
     ClientContextsList mClientContextsList;
     /** Number of connected clients. */
-    int32_t mNumClients;
+    uint32_t mNumClients;
 public:
     explicit Service(PVBOXHGCMSVCHELPERS pHelpers)
@@ -462,5 +462,8 @@
 {
     LogFlowFunc(("New client (%ld) connected\n", u32ClientID));
-    mNumClients++;
+    if (mNumClients < UINT32_MAX)
+        mNumClients++;
+    else
+        AssertMsgFailed(("Max. number of clients reached\n"));
     return VINF_SUCCESS;
 }
@@ -478,6 +481,6 @@
 {
     LogFlowFunc(("Client (%ld) disconnected\n", u32ClientID));
+    Assert(mNumClients > 0);
     mNumClients--;
-    Assert(mNumClients >= 0);
 
     /*
@@ -760,5 +763,5 @@
      * the guest is not running/system is messed up somehow.
      */
-    if (mNumClients <= 0)
+    if (mNumClients == 0)
         return VERR_NOT_FOUND;