diff --git a/reactos/include/ndk/exfuncs.h b/reactos/include/ndk/exfuncs.h
index 58a2d7421ad..43c958a0883 100644
--- a/reactos/include/ndk/exfuncs.h
+++ b/reactos/include/ndk/exfuncs.h
@@ -93,6 +93,15 @@ ExfUnblockPushLock(
     PVOID CurrentWaitBlock
 );
 
+//
+// Resource Functions
+//
+BOOLEAN
+NTAPI
+ExTryToAcquireResourceExclusiveLite(
+    IN PERESOURCE Resource
+);
+
 #endif
 
 //
diff --git a/reactos/include/ndk/extypes.h b/reactos/include/ndk/extypes.h
index 4ca7a30886d..e0c36000b04 100644
--- a/reactos/include/ndk/extypes.h
+++ b/reactos/include/ndk/extypes.h
@@ -104,6 +104,13 @@ extern ULONG NtBuildNumber;
 #define MUTANT_ALL_ACCESS                   (STANDARD_RIGHTS_REQUIRED | \
                                              SYNCHRONIZE | \
                                              MUTANT_QUERY_STATE)
+
+#define TIMER_QUERY_STATE                   0x0001
+#define TIMER_MODIFY_STATE                  0x0002
+#define TIMER_ALL_ACCESS                    (STANDARD_RIGHTS_REQUIRED | \
+                                             SYNCHRONIZE | \
+                                             TIMER_QUERY_STATE | \
+                                             TIMER_MODIFY_STATE)
 #endif
 
 //
diff --git a/reactos/include/ndk/halfuncs.h b/reactos/include/ndk/halfuncs.h
index 358f6255454..01778c9621d 100644
--- a/reactos/include/ndk/halfuncs.h
+++ b/reactos/include/ndk/halfuncs.h
@@ -31,8 +31,10 @@ Author:
 // The DDK steals these away from you.
 //
 #ifdef _MSC_VER
-//#pragma intrinsic(_enable)
-//#pragma intrinsic(_disable)
+void _enable(void);
+void _disable(void);
+#pragma intrinsic(_enable)
+#pragma intrinsic(_disable)
 #endif
 
 //
@@ -208,5 +210,12 @@ HalQueryRealTimeClock(
     IN PTIME_FIELDS RtcTime
 );
 
+NTHALAPI
+VOID
+NTAPI
+HalSetRealTimeClock(
+    IN PTIME_FIELDS RtcTime
+);
+
 #endif
 #endif
diff --git a/reactos/include/ndk/iofuncs.h b/reactos/include/ndk/iofuncs.h
index e3a50f36f72..e559fedf86d 100644
--- a/reactos/include/ndk/iofuncs.h
+++ b/reactos/include/ndk/iofuncs.h
@@ -671,7 +671,6 @@ ZwDeviceIoControlFile(
     IN ULONG OutputBufferSize
 );
 
-#ifdef NTOS_MODE_USER
 NTSYSAPI
 NTSTATUS
 NTAPI
@@ -679,7 +678,6 @@ ZwFlushBuffersFile(
     IN HANDLE FileHandle,
     OUT PIO_STATUS_BLOCK IoStatusBlock
 );
-#endif
 
 NTSYSAPI
 NTSTATUS
diff --git a/reactos/include/ndk/obfuncs.h b/reactos/include/ndk/obfuncs.h
index eb55d2b4447..e9741369ccb 100644
--- a/reactos/include/ndk/obfuncs.h
+++ b/reactos/include/ndk/obfuncs.h
@@ -29,6 +29,16 @@ Author:
 //
 // Object Functions
 //
+NTKERNELAPI
+NTSTATUS
+NTAPI
+ObAssignSecurity(
+    IN PACCESS_STATE AccessState,
+    IN PSECURITY_DESCRIPTOR SecurityDescriptor,
+    IN PVOID Object,
+    IN POBJECT_TYPE Type
+);
+
 NTKERNELAPI
 NTSTATUS
 NTAPI
diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index 854d94d5d76..0efe23bf6c7 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -478,10 +478,10 @@ typedef DWORD FLONG;
 #ifndef __NTDDK_H
 #define MUTANT_QUERY_STATE	0x0001
 #define MUTANT_ALL_ACCESS	(STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|MUTANT_QUERY_STATE)
-#endif
 #define TIMER_QUERY_STATE	0x0001
 #define TIMER_MODIFY_STATE	0x0002
 #define TIMER_ALL_ACCESS	(STANDARD_RIGHTS_REQUIRED|SYNCHRONIZE|TIMER_QUERY_STATE|TIMER_MODIFY_STATE)
+#endif
 /*
  * To prevent gcc compiler warnings, bracket these defines when initialising
  * a  SID_IDENTIFIER_AUTHORITY, eg.
diff --git a/reactos/ntoskrnl/cc/view.c b/reactos/ntoskrnl/cc/view.c
index 87ded521c6a..0227bad7da6 100644
--- a/reactos/ntoskrnl/cc/view.c
+++ b/reactos/ntoskrnl/cc/view.c
@@ -358,7 +358,7 @@ CcRosTrimCache(ULONG Target, ULONG Priority, PULONG NrFreed)
 	     for (i = 0; i < current->Bcb->CacheSegmentSize / PAGE_SIZE; i++)
 	       {
 	         PFN_TYPE Page;
-		 Page = MmGetPhysicalAddress((char*)current->BaseAddress + i * PAGE_SIZE).QuadPart >> PAGE_SHIFT;
+		 Page = (PFN_TYPE)(MmGetPhysicalAddress((char*)current->BaseAddress + i * PAGE_SIZE).QuadPart >> PAGE_SHIFT);
                  Status = MmPageOutPhysicalAddress(Page);
 		 if (!NT_SUCCESS(Status))
 		   {
diff --git a/reactos/ntoskrnl/cm/regobj.c b/reactos/ntoskrnl/cm/regobj.c
index 6ed5f62ca10..a6b75b6fd86 100644
--- a/reactos/ntoskrnl/cm/regobj.c
+++ b/reactos/ntoskrnl/cm/regobj.c
@@ -276,8 +276,8 @@ CmiObjectParse(IN PVOID ParsedObject,
     Length = wcslen(StartPtr);
 
 
-  KeyName.Length = Length * sizeof(WCHAR);
-  KeyName.MaximumLength = KeyName.Length + sizeof(WCHAR);
+  KeyName.Length = (USHORT)Length * sizeof(WCHAR);
+  KeyName.MaximumLength = (USHORT)KeyName.Length + sizeof(WCHAR);
   KeyName.Buffer = ExAllocatePool(NonPagedPool,
 				  KeyName.MaximumLength);
   RtlCopyMemory(KeyName.Buffer,
@@ -751,7 +751,7 @@ CmiObjectQueryName (PVOID ObjectBody,
     {
       ObjectNameInfo->Name.Buffer = (PWCHAR)(ObjectNameInfo + 1);
       ObjectNameInfo->Name.Length = 0;
-      ObjectNameInfo->Name.MaximumLength = Length - sizeof(OBJECT_NAME_INFORMATION);
+      ObjectNameInfo->Name.MaximumLength = (USHORT)Length - sizeof(OBJECT_NAME_INFORMATION);
     }
 
 
@@ -931,13 +931,13 @@ CmiGetLinkTarget(PEREGISTRY_HIVE RegistryHive,
   if (TargetPath->Buffer == NULL && TargetPath->MaximumLength == 0)
     {
       TargetPath->Length = 0;
-      TargetPath->MaximumLength = ValueCell->DataSize + sizeof(WCHAR);
+      TargetPath->MaximumLength = (USHORT)ValueCell->DataSize + sizeof(WCHAR);
       TargetPath->Buffer = ExAllocatePool(NonPagedPool,
 					  TargetPath->MaximumLength);
     }
 
-  TargetPath->Length = min(TargetPath->MaximumLength - sizeof(WCHAR),
-			   (ULONG) ValueCell->DataSize);
+  TargetPath->Length = min((USHORT)TargetPath->MaximumLength - sizeof(WCHAR),
+			   (USHORT)ValueCell->DataSize);
 
   if (ValueCell->DataSize > 0)
     {
diff --git a/reactos/ntoskrnl/deprecated/irq.c b/reactos/ntoskrnl/deprecated/irq.c
index e7c90fa1602..8845090ee57 100644
--- a/reactos/ntoskrnl/deprecated/irq.c
+++ b/reactos/ntoskrnl/deprecated/irq.c
@@ -512,7 +512,7 @@ KiInterruptDispatch3 (ULONG vector, PKIRQ_TRAPFRAME Trapframe)
            DPRINT("PID: %d, TID: %d CS %04x/%04x\n",
                   ((PETHREAD)CurrentThread)->ThreadsProcess->UniqueProcessId,
                   ((PETHREAD)CurrentThread)->Cid.UniqueThread,
-                  Trapframe->SegCs,
+                  Trapframe->Cs,
                   CurrentThread->TrapFrame ? CurrentThread->TrapFrame->SegCs : 0);
            if (CurrentThread->TrapFrame == NULL)
              {
diff --git a/reactos/ntoskrnl/ex/locale.c b/reactos/ntoskrnl/ex/locale.c
index c4ca67db2ba..b8589dd3a29 100644
--- a/reactos/ntoskrnl/ex/locale.c
+++ b/reactos/ntoskrnl/ex/locale.c
@@ -80,7 +80,7 @@ ExpGetCurrentUserUILanguage(IN PWSTR MuiName,
                 if (NT_SUCCESS(Status))
                 {
                     /* Return the language */
-                    *LanguageId = Value;
+                    *LanguageId = (USHORT)Value;
                 }
             }
             else
diff --git a/reactos/ntoskrnl/ex/sysinfo.c b/reactos/ntoskrnl/ex/sysinfo.c
index 0556c7eec2a..06b74006ac3 100644
--- a/reactos/ntoskrnl/ex/sysinfo.c
+++ b/reactos/ntoskrnl/ex/sysinfo.c
@@ -71,7 +71,7 @@ ExGetCurrentProcessorCpuUsage (
 	ScaledIdle = Prcb->IdleThread->KernelTime * 100;
 	TotalTime = Prcb->KernelTime + Prcb->UserTime;
 	if (TotalTime != 0)
-		*CpuUsage = 100 - (ScaledIdle / TotalTime);
+		*CpuUsage = (ULONG)(100 - (ScaledIdle / TotalTime));
 	else
 		*CpuUsage = 0;
 }
@@ -211,7 +211,9 @@ NtQuerySystemEnvironmentValue (IN	PUNICODE_STRING	VariableName,
     /*
      * Get the environment variable
      */
-    Result = HalGetEnvironmentVariable(AName.Buffer, ValueBufferLength, Value);
+    Result = HalGetEnvironmentVariable(AName.Buffer,
+                                       (USHORT)ValueBufferLength,
+                                       Value);
     if(!Result)
     {
       RtlFreeAnsiString(&AName);
diff --git a/reactos/ntoskrnl/fs/name.c b/reactos/ntoskrnl/fs/name.c
index 49d87c5141d..2e9f09ddb75 100644
--- a/reactos/ntoskrnl/fs/name.c
+++ b/reactos/ntoskrnl/fs/name.c
@@ -297,13 +297,13 @@ FsRtlDissectDbcs(IN ANSI_STRING Name,
     }
 
     /* Now we have the First Part */
-    FirstPart->Length = (i-FirstLoop);
+    FirstPart->Length = (USHORT)(i - FirstLoop);
     FirstPart->MaximumLength = FirstPart->Length; /* +2?? */
     FirstPart->Buffer = &Name.Buffer[FirstLoop];
 
     /* Make the second part if something is still left */
     if (i<Name.Length) {
-        RemainingPart->Length = (Name.Length - (i+1));
+        RemainingPart->Length = (USHORT)(Name.Length - (i+1));
         RemainingPart->MaximumLength = RemainingPart->Length; /* +2?? */
         RemainingPart->Buffer = &Name.Buffer[i+1];
     }
diff --git a/reactos/ntoskrnl/fs/util.c b/reactos/ntoskrnl/fs/util.c
index 8f9704c56bf..58853bef3c5 100644
--- a/reactos/ntoskrnl/fs/util.c
+++ b/reactos/ntoskrnl/fs/util.c
@@ -42,8 +42,10 @@ RtlpInitializeResources(VOID)
     ULONG i;
 
     /* Allocate the Resource Buffer */
-    FsRtlpResources = FsRtlAllocatePool(NonPagedPool,
-                                        FSRTL_MAX_RESOURCES*sizeof(ERESOURCE));
+    FsRtlpResources = FsRtlAllocatePoolWithTag(NonPagedPool,
+                                               FSRTL_MAX_RESOURCES *
+                                               sizeof(ERESOURCE),
+                                               TAG('F', 's', 'R', 'e'));
 
     /* Initialize the Resources */
     for (i = 0; i < FSRTL_MAX_RESOURCES; i++)
diff --git a/reactos/ntoskrnl/io/pnpmgr/pnpmgr.c b/reactos/ntoskrnl/io/pnpmgr/pnpmgr.c
index 75309f193d3..96b282aba87 100644
--- a/reactos/ntoskrnl/io/pnpmgr/pnpmgr.c
+++ b/reactos/ntoskrnl/io/pnpmgr/pnpmgr.c
@@ -593,7 +593,7 @@ IoOpenDeviceRegistryKey(IN PDEVICE_OBJECT DeviceObject,
       return STATUS_INSUFFICIENT_RESOURCES;
 
    KeyName.Length = 0;
-   KeyName.MaximumLength = KeyNameLength;
+   KeyName.MaximumLength = (USHORT)KeyNameLength;
    KeyName.Buffer = KeyNameBuffer;
 
    /*
@@ -619,7 +619,7 @@ IoOpenDeviceRegistryKey(IN PDEVICE_OBJECT DeviceObject,
          ExFreePool(KeyNameBuffer);
          return Status;
       }
-      KeyName.Length += DriverKeyLength - sizeof(UNICODE_NULL);
+      KeyName.Length += (USHORT)DriverKeyLength - sizeof(UNICODE_NULL);
    }
    else
    {
@@ -750,7 +750,7 @@ IopGetBusTypeGuidIndex(LPGUID BusTypeGuid)
                  sizeof(GUID));
 
    /* The new entry is the index */
-   FoundIndex = IopBusTypeGuidList->GuidCount;
+   FoundIndex = (USHORT)IopBusTypeGuidList->GuidCount;
    IopBusTypeGuidList->GuidCount++;
 
 Quickie:
@@ -928,7 +928,7 @@ IopInitiatePnpIrp(PDEVICE_OBJECT DeviceObject,
    Irp->IoStatus.Information = 0;
 
    IrpSp = IoGetNextIrpStackLocation(Irp);
-   IrpSp->MinorFunction = MinorFunction;
+   IrpSp->MinorFunction = (UCHAR)MinorFunction;
 
    if (Stack)
    {
@@ -1618,14 +1618,14 @@ IopGetParentIdPrefix(PDEVICE_NODE DeviceNode,
          Status = STATUS_UNSUCCESSFUL;
       else
       {
-         KeyValue.Length = KeyValue.MaximumLength = ParentIdPrefixInformation->DataLength;
+         KeyValue.Length = KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
          KeyValue.Buffer = (PWSTR)ParentIdPrefixInformation->Data;
       }
       goto cleanup;
    }
    if (Status != STATUS_OBJECT_NAME_NOT_FOUND)
    {
-      KeyValue.Length = KeyValue.MaximumLength = ParentIdPrefixInformation->DataLength;
+      KeyValue.Length = KeyValue.MaximumLength = (USHORT)ParentIdPrefixInformation->DataLength;
       KeyValue.Buffer = (PWSTR)ParentIdPrefixInformation->Data;
       goto cleanup;
    }
@@ -2711,7 +2711,7 @@ IopEnumerateDetectedDevices(
       IndexDevice++;
 
       /* Open device key */
-      DeviceName.Length = DeviceName.MaximumLength = pDeviceInformation->NameLength;
+      DeviceName.Length = DeviceName.MaximumLength = (USHORT)pDeviceInformation->NameLength;
       DeviceName.Buffer = pDeviceInformation->Name;
       InitializeObjectAttributes(&ObjectAttributes, &DeviceName, OBJ_KERNEL_HANDLE, hDevicesKey, NULL);
       Status = ZwOpenKey(
@@ -2832,7 +2832,7 @@ IopEnumerateDetectedDevices(
                goto cleanup;
             }
             IndexSubKey++;
-            DeviceName.Length = DeviceName.MaximumLength = pDeviceInformation->NameLength;
+            DeviceName.Length = DeviceName.MaximumLength = (USHORT)pDeviceInformation->NameLength;
             DeviceName.Buffer = pDeviceInformation->Name;
 
             Status = IopEnumerateDetectedDevices(
@@ -2878,7 +2878,7 @@ IopEnumerateDetectedDevices(
       else
       {
          /* Assign hardware id to this device */
-         ValueName.Length = ValueName.MaximumLength = pValueInformation->DataLength;
+         ValueName.Length = ValueName.MaximumLength = (USHORT)pValueInformation->DataLength;
          ValueName.Buffer = (PWCHAR)pValueInformation->Data;
          if (ValueName.Length >= sizeof(WCHAR) && ValueName.Buffer[ValueName.Length / sizeof(WCHAR) - 1] == UNICODE_NULL)
             ValueName.Length -= sizeof(WCHAR);
diff --git a/reactos/ntoskrnl/ke/i386/kiinit.c b/reactos/ntoskrnl/ke/i386/kiinit.c
index ace598b406a..31b3f005733 100644
--- a/reactos/ntoskrnl/ke/i386/kiinit.c
+++ b/reactos/ntoskrnl/ke/i386/kiinit.c
@@ -438,21 +438,21 @@ KiInitializeKernel(IN PKPROCESS InitProcess,
     LdrInit1();
 
     /* Set the NX Support policy */
-    SharedUserData->NXSupportPolicy = NXSupportPolicy;
+    SharedUserData->NXSupportPolicy = (UCHAR)NXSupportPolicy;
 
     /* Set basic CPU Features that user mode can read */
     SharedUserData->ProcessorFeatures[PF_MMX_INSTRUCTIONS_AVAILABLE] =
-        (KeFeatureBits & KF_MMX);
+        (KeFeatureBits & KF_MMX) ? TRUE: FALSE;
     SharedUserData->ProcessorFeatures[PF_COMPARE_EXCHANGE_DOUBLE] =
-        (KeFeatureBits & KF_CMPXCHG8B);
+        (KeFeatureBits & KF_CMPXCHG8B) ? TRUE: FALSE;
     SharedUserData->ProcessorFeatures[PF_XMMI_INSTRUCTIONS_AVAILABLE] =
-        ((KeFeatureBits & KF_FXSR) && (KeFeatureBits & KF_XMMI));
+        ((KeFeatureBits & KF_FXSR) && (KeFeatureBits & KF_XMMI)) ? TRUE: FALSE;
     SharedUserData->ProcessorFeatures[PF_XMMI64_INSTRUCTIONS_AVAILABLE] =
-        ((KeFeatureBits & KF_FXSR) && (KeFeatureBits & KF_XMMI64));
+        ((KeFeatureBits & KF_FXSR) && (KeFeatureBits & KF_XMMI64)) ? TRUE: FALSE;
     SharedUserData->ProcessorFeatures[PF_3DNOW_INSTRUCTIONS_AVAILABLE] =
-        (KeFeatureBits & KF_3DNOW);
+        (KeFeatureBits & KF_3DNOW) ? TRUE: FALSE;
     SharedUserData->ProcessorFeatures[PF_RDTSC_INSTRUCTION_AVAILABLE] =
-        (KeFeatureBits & KF_RDTSC);
+        (KeFeatureBits & KF_RDTSC) ? TRUE: FALSE;
 
     /* Set up the thread-related fields in the PRCB */
     Prcb->CurrentThread = InitThread;
@@ -514,7 +514,7 @@ KiGetMachineBootPointers(IN PKGDTENTRY *Gdt,
 {
     KDESCRIPTOR GdtDescriptor, IdtDescriptor;
     KGDTENTRY TssSelector, PcrSelector;
-    ULONG Tr, Fs;
+    USHORT Tr, Fs;
 
     /* Get GDT and IDT descriptors */
     Ke386GetGlobalDescriptorTable(GdtDescriptor);
@@ -666,7 +666,7 @@ AppCpuInit:
                        InitialThread,
                        (PVOID)InitialStack,
                        (PKPRCB)__readfsdword(KPCR_PRCB),
-                       Cpu,
+                       (CCHAR)Cpu,
                        KeLoaderBlock);
 
     /* Set the priority of this thread to 0 */
diff --git a/reactos/ntoskrnl/ke/i386/v86vdm.c b/reactos/ntoskrnl/ke/i386/v86vdm.c
index 6039657a7e8..517aba910ae 100644
--- a/reactos/ntoskrnl/ke/i386/v86vdm.c
+++ b/reactos/ntoskrnl/ke/i386/v86vdm.c
@@ -94,8 +94,8 @@ Ke386CallBios(IN ULONG Int,
     /* Save the old offset and base, and set the new ones */
     OldOffset = Process->IopmOffset;
     OldBase = Tss->IoMapBase;
-    Process->IopmOffset = IOPM_OFFSET;
-    Tss->IoMapBase = IOPM_OFFSET;
+    Process->IopmOffset = (USHORT)IOPM_OFFSET;
+    Tss->IoMapBase = (USHORT)IOPM_OFFSET;
 
     /* Switch stacks and work the magic */
     Ki386SetupAndExitToV86Mode(VdmTeb);
diff --git a/reactos/ntoskrnl/ke/thrdschd.c b/reactos/ntoskrnl/ke/thrdschd.c
index 95a49bd8342..e27f5c3b6ca 100644
--- a/reactos/ntoskrnl/ke/thrdschd.c
+++ b/reactos/ntoskrnl/ke/thrdschd.c
@@ -281,7 +281,7 @@ KiAdjustQuantumThread(IN PKTHREAD Thread)
                  * due to the current ""scheduler"" in ROS, it can't be done
                  * cleanly since it actualyl dispatches threads instead.
                  */
-                Thread->Priority = Priority;
+                Thread->Priority = (SCHAR)Priority;
             }
             else
             {
@@ -310,7 +310,7 @@ KiSetPriorityThread(PKTHREAD Thread,
     if (OldPriority != Priority)
     {
         /* Set it */
-        Thread->Priority = Priority;
+        Thread->Priority = (SCHAR)Priority;
 
         /* Choose action based on thread's state */
         if (Thread->State == Ready)
@@ -383,7 +383,7 @@ KiSetAffinityThread(IN PKTHREAD Thread,
 {
     KAFFINITY OldAffinity;
     ULONG ProcessorMask;
-    ULONG i;
+    CCHAR i;
     PKPCR Pcr;
 
     /* Make sure that the affinity is valid */
diff --git a/reactos/ntoskrnl/ldr/loader.c b/reactos/ntoskrnl/ldr/loader.c
index 1e07e06c23d..dc05771b429 100644
--- a/reactos/ntoskrnl/ldr/loader.c
+++ b/reactos/ntoskrnl/ldr/loader.c
@@ -1145,7 +1145,7 @@ LdrPEGetOrLoadModule (
             RtlCopyMemory(NameBuffer, Module->FullDllName.Buffer, PathLength);
             RtlCopyMemory(NameBuffer + (PathLength / sizeof(WCHAR)), DriverName.Buffer, DriverName.Length);
             NameString.Buffer = NameBuffer;
-            NameString.MaximumLength = NameString.Length = PathLength + DriverName.Length;
+            NameString.MaximumLength = NameString.Length = (USHORT)PathLength + DriverName.Length;
 
             /* NULL-terminate */
             NameString.MaximumLength += sizeof(WCHAR);
diff --git a/reactos/ntoskrnl/lpc/reply.c b/reactos/ntoskrnl/lpc/reply.c
index e67db081f06..21de54a18ba 100644
--- a/reactos/ntoskrnl/lpc/reply.c
+++ b/reactos/ntoskrnl/lpc/reply.c
@@ -65,7 +65,7 @@ EiReplyOrRequestPort (IN	PEPORT		Port,
 
    MessageReply->Message.ClientId.UniqueProcess = PsGetCurrentProcessId();
    MessageReply->Message.ClientId.UniqueThread = PsGetCurrentThreadId();
-   MessageReply->Message.u2.s2.Type = MessageType;
+   MessageReply->Message.u2.s2.Type = (CSHORT)MessageType;
    MessageReply->Message.MessageId = InterlockedIncrementUL(&LpcpNextMessageId);
 
    KeAcquireSpinLock(&Port->Lock, &oldIrql);
@@ -276,7 +276,7 @@ NtReplyWaitReceivePortEx(IN HANDLE PortHandle,
 
        CRequest = (PEPORT_CONNECT_REQUEST_MESSAGE)&Request->Message;
        memcpy(&Header, &Request->Message, sizeof(PORT_MESSAGE));
-       Header.u1.s1.DataLength = CRequest->ConnectDataLength;
+       Header.u1.s1.DataLength = (CSHORT)CRequest->ConnectDataLength;
        Header.u1.s1.TotalLength = Header.u1.s1.DataLength + sizeof(PORT_MESSAGE);
        
        if (PreviousMode != KernelMode)
diff --git a/reactos/ntoskrnl/mm/pagefile.c b/reactos/ntoskrnl/mm/pagefile.c
index b6253b2029e..5ce6407a4c7 100644
--- a/reactos/ntoskrnl/mm/pagefile.c
+++ b/reactos/ntoskrnl/mm/pagefile.c
@@ -586,7 +586,7 @@ MmDumpToPagingFile(ULONG BugCode,
    RetrievalPointers = PagingFileList[MmCoreDumpPageFile]->RetrievalPointers;
 
    /* Dump the header. */
-   MdlMap[0] = MmGetPhysicalAddress(MmCoreDumpPageFrame).QuadPart >> PAGE_SHIFT;
+   MdlMap[0] = (ULONG)(MmGetPhysicalAddress(MmCoreDumpPageFrame).QuadPart >> PAGE_SHIFT);
 #if defined(__GNUC__)
 
    DiskOffset = MmGetOffsetPageFile(RetrievalPointers, (LARGE_INTEGER)0LL);
diff --git a/reactos/ntoskrnl/ob/obdir.c b/reactos/ntoskrnl/ob/obdir.c
index 9c6df161363..a0cfdda2bba 100644
--- a/reactos/ntoskrnl/ob/obdir.c
+++ b/reactos/ntoskrnl/ob/obdir.c
@@ -163,7 +163,7 @@ ObpLookupEntryDirectory(IN POBJECT_DIRECTORY Directory,
 
     /* Save the result */
     Context->HashValue = HashValue;
-    Context->HashIndex = HashIndex;
+    Context->HashIndex = (USHORT)HashIndex;
 
     /* Get the root entry and set it as our lookup bucket */
     AllocatedEntry = &Directory->HashBuckets[HashIndex];
diff --git a/reactos/ntoskrnl/ob/obinit.c b/reactos/ntoskrnl/ob/obinit.c
index 395b867fbbe..978888ad0ea 100644
--- a/reactos/ntoskrnl/ob/obinit.c
+++ b/reactos/ntoskrnl/ob/obinit.c
@@ -61,7 +61,7 @@ INIT_FUNCTION
 NTAPI
 ObInit2(VOID)
 {
-    ULONG i;
+    CCHAR i;
     PKPRCB Prcb;
     PNPAGED_LOOKASIDE_LIST CurrentList = NULL;
 
diff --git a/reactos/ntoskrnl/ob/oblife.c b/reactos/ntoskrnl/ob/oblife.c
index 4dd515dddb5..99c2b06f710 100644
--- a/reactos/ntoskrnl/ob/oblife.c
+++ b/reactos/ntoskrnl/ob/oblife.c
@@ -332,8 +332,8 @@ ObpCaptureObjectName(IN OUT PUNICODE_STRING CapturedName,
                 }
 
                 /* Setup the string */
-                CapturedName->Length = StringLength;
-                CapturedName->MaximumLength = MaximumLength;
+                CapturedName->Length = (USHORT)StringLength;
+                CapturedName->MaximumLength = (USHORT)MaximumLength;
                 CapturedName->Buffer = StringBuffer;
 
                 /* Make sure we have a buffer */
diff --git a/reactos/ntoskrnl/ob/symlink.c b/reactos/ntoskrnl/ob/symlink.c
index 088db566081..1f710720b20 100644
--- a/reactos/ntoskrnl/ob/symlink.c
+++ b/reactos/ntoskrnl/ob/symlink.c
@@ -13,10 +13,6 @@
 #define NDEBUG
 #include <internal/debug.h>
 
-#if defined (ALLOC_PRAGMA)
-#pragma alloc_text(INIT, ObInitSymbolicLinkImplementation)
-#endif
-
 /* GLOBALS ******************************************************************/
 
 POBJECT_TYPE ObSymbolicLinkType = NULL;
@@ -165,8 +161,8 @@ ObpParseSymbolicLink(IN PVOID ParsedObject,
     if (NewTargetPath != FullPath->Buffer) ExFreePool(FullPath->Buffer);
 
     /* Update the path values */
-    FullPath->Length = LengthUsed;
-    FullPath->MaximumLength = MaximumLength;
+    FullPath->Length = (USHORT)LengthUsed;
+    FullPath->MaximumLength = (USHORT)MaximumLength;
     FullPath->Buffer = NewTargetPath;
 
     /* Tell the parse routine to start reparsing */
@@ -247,7 +243,7 @@ NtCreateSymbolicLinkObject(OUT PHANDLE LinkHandle,
     {
         /* Round it down */
         CapturedLinkTarget.MaximumLength =
-            ALIGN_DOWN(CapturedLinkTarget.MaximumLength, WCHAR);
+            (USHORT)ALIGN_DOWN(CapturedLinkTarget.MaximumLength, WCHAR);
     }
 
     /* Fail if the length is odd, or if the maximum is smaller or 0 */
diff --git a/reactos/ntoskrnl/ps/process.c b/reactos/ntoskrnl/ps/process.c
index 4c46dec4624..19c7a7161df 100644
--- a/reactos/ntoskrnl/ps/process.c
+++ b/reactos/ntoskrnl/ps/process.c
@@ -658,9 +658,9 @@ PspCreateProcess(OUT PHANDLE ProcessHandle,
     if (!NT_SUCCESS(Status)) goto Cleanup;
 
     /* Compute Quantum and Priority */
-    Process->Pcb.BasePriority = PspComputeQuantumAndPriority(Process,
-                                                             0,
-                                                             &Quantum);
+    Process->Pcb.BasePriority = (SCHAR)PspComputeQuantumAndPriority(Process,
+                                                                    0,
+                                                                    &Quantum);
     Process->Pcb.QuantumReset = Quantum;
 
     /* Check if we have a parent other then the initial system process */
@@ -912,7 +912,7 @@ BOOLEAN
 NTAPI
 PsGetProcessExitProcessCalled(PEPROCESS Process)
 {
-    return Process->ProcessExiting;
+    return (BOOLEAN)Process->ProcessExiting;
 }
 
 /*
@@ -1083,7 +1083,7 @@ NTAPI
 PsSetProcessPriorityClass(PEPROCESS Process,
                           ULONG PriorityClass)
 {
-    Process->PriorityClass = PriorityClass;
+    Process->PriorityClass = (UCHAR)PriorityClass;
 }
 
 /*
diff --git a/reactos/ntoskrnl/ps/security.c b/reactos/ntoskrnl/ps/security.c
index bd6af32b2df..de5363ec96e 100644
--- a/reactos/ntoskrnl/ps/security.c
+++ b/reactos/ntoskrnl/ps/security.c
@@ -141,7 +141,7 @@ PspWriteTebImpersonationInfo(IN PETHREAD Thread,
         }
 
         /* Check if the thread is impersonating */
-        IsImpersonating = Thread->ActiveImpersonationInfo;
+        IsImpersonating = (BOOLEAN)Thread->ActiveImpersonationInfo;
         if (IsImpersonating)
         {
             /* Set TEB data */
diff --git a/reactos/ntoskrnl/rtl/libsupp.c b/reactos/ntoskrnl/rtl/libsupp.c
index fafe20bf6e8..3e1e9d6d74e 100644
--- a/reactos/ntoskrnl/rtl/libsupp.c
+++ b/reactos/ntoskrnl/rtl/libsupp.c
@@ -382,8 +382,8 @@ RtlpCreateUnicodeString(
                   Source,
                   Length);
 
-   UniDest->MaximumLength = Length;
-   UniDest->Length = Length - sizeof (WCHAR);
+   UniDest->MaximumLength = (USHORT)Length;
+   UniDest->Length = (USHORT)Length - sizeof (WCHAR);
 
    return TRUE;
 }
diff --git a/reactos/ntoskrnl/rtl/misc.c b/reactos/ntoskrnl/rtl/misc.c
index d61a6955777..5739852f847 100644
--- a/reactos/ntoskrnl/rtl/misc.c
+++ b/reactos/ntoskrnl/rtl/misc.c
@@ -73,9 +73,9 @@ RtlGetVersion(IN OUT PRTL_OSVERSIONINFOW lpVersionInformation)
       if (lpVersionInformation->dwOSVersionInfoSize == sizeof(OSVERSIONINFOEXW))
       {
          RTL_OSVERSIONINFOEXW *InfoEx = (RTL_OSVERSIONINFOEXW *)lpVersionInformation;
-         InfoEx->wServicePackMajor = (NtOSCSDVersion >> 8) & 0xFF;
-         InfoEx->wServicePackMinor = NtOSCSDVersion & 0xFF;
-         InfoEx->wSuiteMask = SharedUserData->SuiteMask;
+         InfoEx->wServicePackMajor = (USHORT)(NtOSCSDVersion >> 8) & 0xFF;
+         InfoEx->wServicePackMinor = (USHORT)(NtOSCSDVersion & 0xFF);
+         InfoEx->wSuiteMask = (USHORT)SharedUserData->SuiteMask;
          InfoEx->wProductType = SharedUserData->NtProductType;
       }
 
diff --git a/reactos/ntoskrnl/se/sd.c b/reactos/ntoskrnl/se/sd.c
index 170c19e9796..3d27f6910f9 100644
--- a/reactos/ntoskrnl/se/sd.c
+++ b/reactos/ntoskrnl/se/sd.c
@@ -810,7 +810,7 @@ SeQuerySecurityDescriptorInfo(IN PSECURITY_INFORMATION SecurityInformation,
   /* Build the new security descrtiptor */
   RtlCreateSecurityDescriptorRelative(RelSD,
 			              SECURITY_DESCRIPTOR_REVISION);
-  RelSD->Control = Control;
+  RelSD->Control = (USHORT)Control;
 
   Current = (ULONG_PTR)(RelSD + 1);
 
diff --git a/reactos/ntoskrnl/se/semgr.c b/reactos/ntoskrnl/se/semgr.c
index d4e863c2e93..ba5d2ef7698 100644
--- a/reactos/ntoskrnl/se/semgr.c
+++ b/reactos/ntoskrnl/se/semgr.c
@@ -340,7 +340,7 @@ SeDefaultObjectMethod(PVOID Object,
       RtlCreateSecurityDescriptor(NewSd,
 				  SECURITY_DESCRIPTOR_REVISION1);
       /* We always build a self-relative descriptor */
-      NewSd->Control = Control | SE_SELF_RELATIVE;
+      NewSd->Control = (USHORT)Control | SE_SELF_RELATIVE;
 
       Current = (ULONG_PTR)NewSd + sizeof(SECURITY_DESCRIPTOR);
 
@@ -754,7 +754,7 @@ SeAssignSecurity(PSECURITY_DESCRIPTOR _ParentDescriptor OPTIONAL,
   RtlCreateSecurityDescriptor(Descriptor,
 			      SECURITY_DESCRIPTOR_REVISION);
 
-  Descriptor->Control = Control | SE_SELF_RELATIVE;
+  Descriptor->Control = (USHORT)Control | SE_SELF_RELATIVE;
 
   Current = (ULONG_PTR)Descriptor + sizeof(SECURITY_DESCRIPTOR);
 
diff --git a/reactos/ntoskrnl/se/token.c b/reactos/ntoskrnl/se/token.c
index 841276a782c..b50e7803ea4 100644
--- a/reactos/ntoskrnl/se/token.c
+++ b/reactos/ntoskrnl/se/token.c
@@ -621,7 +621,7 @@ SeImpersonateClient(IN PSECURITY_CLIENT_CONTEXT ClientContext,
   PsImpersonateClient(ServerThread,
 		      ClientContext->ClientToken,
 		      1,
-		      (ULONG)b,
+		      b,
 		      ClientContext->SecurityQos.ImpersonationLevel);
 }