diff --git a/base/system/smss/smsbapi.c b/base/system/smss/smsbapi.c
index 60a081a548c..e1b21f7bdb3 100644
--- a/base/system/smss/smsbapi.c
+++ b/base/system/smss/smsbapi.c
@@ -47,7 +47,7 @@ SmpSbCreateSession(IN PVOID Reserved,
     PSB_CREATE_SESSION_MSG CreateSessionMsg;
 
     /* Write out the create session message including its initial process */
-    CreateSessionMsg = &SbApiMsg.CreateSession;
+    CreateSessionMsg = &SbApiMsg.u.CreateSession;
     CreateSessionMsg->ProcessInfo = *ProcessInformation;
     CreateSessionMsg->MuSessionId = MuSessionId;
     if (DbgClientId)
diff --git a/base/system/smss/smsubsys.c b/base/system/smss/smsubsys.c
index a504a185900..ecae4cb1db0 100644
--- a/base/system/smss/smsubsys.c
+++ b/base/system/smss/smsubsys.c
@@ -149,8 +149,8 @@ SmpLoadSubSystem(IN PUNICODE_STRING FileName,
     RTL_USER_PROCESS_INFORMATION ProcessInformation;
     LARGE_INTEGER Timeout;
     PVOID State;
-    PSB_CREATE_PROCESS_MSG CreateProcess = &SbApiMsg.CreateProcess;
-    PSB_CREATE_SESSION_MSG CreateSession = &SbApiMsg.CreateSession;
+    PSB_CREATE_PROCESS_MSG CreateProcess = &SbApiMsg.u.CreateProcess;
+    PSB_CREATE_SESSION_MSG CreateSession = &SbApiMsg.u.CreateSession;
 
     /* Make sure this is a found subsystem */
     if (Flags & SMP_INVALID_PATH)
diff --git a/sdk/include/reactos/subsys/sm/smmsg.h b/sdk/include/reactos/subsys/sm/smmsg.h
index e72f0917fb2..ada3ae670bc 100644
--- a/sdk/include/reactos/subsys/sm/smmsg.h
+++ b/sdk/include/reactos/subsys/sm/smmsg.h
@@ -211,6 +211,10 @@ C_ASSERT(sizeof(SB_CREATE_PROCESS_MSG) == 0x18);
 C_ASSERT(sizeof(SB_CREATE_PROCESS_MSG) == 0x28);
 #endif
 
+#ifdef CreateProcess
+#undef CreateProcess
+#endif
+
 //
 // When the server connects to a client, this structure is exchanged
 //
@@ -239,7 +243,7 @@ typedef struct _SB_API_MSG
                 SB_TERMINATE_SESSION_MSG TerminateSession;
                 SB_FOREIGN_SESSION_COMPLETE_MSG ForeignSessionComplete;
                 SB_CREATE_PROCESS_MSG CreateProcess;
-            };
+            } u;
         };
     };
 } SB_API_MSG, *PSB_API_MSG;
diff --git a/subsystems/csr/csrsrv/session.c b/subsystems/csr/csrsrv/session.c
index 381bb16df6f..75aff353638 100644
--- a/subsystems/csr/csrsrv/session.c
+++ b/subsystems/csr/csrsrv/session.c
@@ -207,7 +207,7 @@ BOOLEAN
 NTAPI
 CsrSbCreateSession(IN PSB_API_MSG ApiMessage)
 {
-    PSB_CREATE_SESSION_MSG CreateSession = &ApiMessage->CreateSession;
+    PSB_CREATE_SESSION_MSG CreateSession = &ApiMessage->u.CreateSession;
     HANDLE hProcess, hThread;
     PCSR_PROCESS CsrProcess;
     PCSR_THREAD CsrThread;