diff --git a/drivers/network/tcpip/CMakeLists.txt b/drivers/network/tcpip/CMakeLists.txt
index ce3712ddb0e..13c0ee43020 100644
--- a/drivers/network/tcpip/CMakeLists.txt
+++ b/drivers/network/tcpip/CMakeLists.txt
@@ -6,6 +6,12 @@ set(LWIP_INCLUDE_DIRS
 )
 include(${LWIP_DIR}/src/Filelists.cmake)
 add_dependencies(lwipcore xdk)
+
+if(MSVC AND ARCH STREQUAL "amd64")
+    # lwip is 3rd party code - suppress C4267 warnings
+    target_compile_options(lwipcore PRIVATE "/wd4267")
+endif()
+
 add_subdirectory(ip)
 
 add_definitions(
diff --git a/win32ss/printing/base/winspool/printerdata.c b/win32ss/printing/base/winspool/printerdata.c
index c113cf4c840..a5b93166f61 100644
--- a/win32ss/printing/base/winspool/printerdata.c
+++ b/win32ss/printing/base/winspool/printerdata.c
@@ -347,7 +347,7 @@ GetPrinterDataExA(HANDLE hPrinter, LPCSTR pKeyName, LPCSTR pValueName, LPDWORD p
     if (pKeyName)
     {
         // Convert pKeyName to a Unicode string pwszKeyName
-        cch = strlen(pKeyName);
+        cch = (DWORD)strlen(pKeyName);
 
         pwszKeyName = HeapAlloc(hProcessHeap, 0, (cch + 1) * sizeof(WCHAR));
         if (!pwszKeyName)
@@ -363,7 +363,7 @@ GetPrinterDataExA(HANDLE hPrinter, LPCSTR pKeyName, LPCSTR pValueName, LPDWORD p
     if (pValueName)
     {
         // Convert pValueName to a Unicode string pwszValueName
-        cch = strlen(pValueName);
+        cch = (DWORD)strlen(pValueName);
 
         pwszValueName = HeapAlloc(hProcessHeap, 0, (cch + 1) * sizeof(WCHAR));
         if (!pwszValueName)
@@ -561,7 +561,7 @@ SetPrinterDataExA(HANDLE hPrinter, LPCSTR pKeyName, LPCSTR pValueName, DWORD Typ
     if (pKeyName)
     {
         // Convert pKeyName to a Unicode string pwszKeyName
-        cch = strlen(pKeyName);
+        cch = (DWORD)strlen(pKeyName);
 
         pwszKeyName = HeapAlloc(hProcessHeap, 0, (cch + 1) * sizeof(WCHAR));
         if (!pwszKeyName)
@@ -577,7 +577,7 @@ SetPrinterDataExA(HANDLE hPrinter, LPCSTR pKeyName, LPCSTR pValueName, DWORD Typ
     if (pValueName)
     {
         // Convert pValueName to a Unicode string pwszValueName
-        cch = strlen(pValueName);
+        cch = (DWORD)strlen(pValueName);
 
         pwszValueName = HeapAlloc(hProcessHeap, 0, (cch + 1) * sizeof(WCHAR));
         if (!pwszValueName)
diff --git a/win32ss/printing/monitors/localmon/ports.c b/win32ss/printing/monitors/localmon/ports.c
index 47ebc61cf37..3b1909a2a07 100644
--- a/win32ss/printing/monitors/localmon/ports.c
+++ b/win32ss/printing/monitors/localmon/ports.c
@@ -45,7 +45,7 @@ _GetNonspooledPortName(PCWSTR pwszPortNameWithoutColon, PWSTR* ppwszNonspooledPo
 {
     DWORD cchPortNameWithoutColon;
 
-    cchPortNameWithoutColon = wcslen(pwszPortNameWithoutColon);
+    cchPortNameWithoutColon = (DWORD)wcslen(pwszPortNameWithoutColon);
 
     *ppwszNonspooledPortName = DllAllocSplMem((cchNonspooledPrefix + cchPortNameWithoutColon + 1) * sizeof(WCHAR));
     if (!*ppwszNonspooledPortName)
@@ -192,7 +192,7 @@ _CreateNonspooledPort(PLOCALMON_PORT pPort)
         goto Cleanup;
     }
 
-    cchPortNameWithoutColon = wcslen(pwszPortNameWithoutColon);
+    cchPortNameWithoutColon = (DWORD)wcslen(pwszPortNameWithoutColon);
 
     // The spooler has usually remapped the legacy port to a named pipe of the format in wszSpoolerNamedPipe.
     // Construct the device name of this pipe.
diff --git a/win32ss/printing/monitors/localmon/tools.c b/win32ss/printing/monitors/localmon/tools.c
index e4c15e81125..f430b4dd3bd 100644
--- a/win32ss/printing/monitors/localmon/tools.c
+++ b/win32ss/printing/monitors/localmon/tools.c
@@ -144,7 +144,7 @@ GetPortNameWithoutColon(PCWSTR pwszPortName, PWSTR* ppwszPortNameWithoutColon)
     DWORD cchPortNameWithoutColon;
 
     // Compute the string length of pwszPortNameWithoutColon.
-    cchPortNameWithoutColon = wcslen(pwszPortName) - 1;
+    cchPortNameWithoutColon = (DWORD)wcslen(pwszPortName) - 1;
 
     // Check if pwszPortName really has a colon as the last character.
     if (pwszPortName[cchPortNameWithoutColon] != L':')
diff --git a/win32ss/printing/providers/localspl/jobs.c b/win32ss/printing/providers/localspl/jobs.c
index 99e326ab815..630dbd41a0c 100644
--- a/win32ss/printing/providers/localspl/jobs.c
+++ b/win32ss/printing/providers/localspl/jobs.c
@@ -330,7 +330,7 @@ CreateJob(PLOCAL_PRINTER_HANDLE pPrinterHandle)
         goto Cleanup;
     }
 
-    cchMachineName = wcslen(pwszMachineName);
+    cchMachineName = (DWORD)wcslen(pwszMachineName);
     pJob->pwszMachineName = DllAllocSplMem((cchMachineName + cchDoubleBackslash + 1) * sizeof(WCHAR));
     CopyMemory(pJob->pwszMachineName, wszDoubleBackslash, cchDoubleBackslash * sizeof(WCHAR));
     CopyMemory(&pJob->pwszMachineName[cchDoubleBackslash], pwszMachineName, (cchMachineName + 1) * sizeof(WCHAR));
diff --git a/win32ss/printing/providers/localspl/printers.c b/win32ss/printing/providers/localspl/printers.c
index f323599e3b0..04bf6f26599 100644
--- a/win32ss/printing/providers/localspl/printers.c
+++ b/win32ss/printing/providers/localspl/printers.c
@@ -1465,7 +1465,7 @@ LocalOpenPrinter(PWSTR lpPrinterName, HANDLE* phPrinter, PPRINTER_DEFAULTSW pDef
     if (pwszSecondParameter)
         cchFirstParameter = pwszSecondParameter - p;
     else
-        cchFirstParameter = wcslen(lpPrinterName);
+        cchFirstParameter = (DWORD)wcslen(lpPrinterName);
 
     // We must have at least one parameter.
     if (!cchFirstParameter && !pwszSecondParameter)
diff --git a/win32ss/printing/providers/localspl/printingthread.c b/win32ss/printing/providers/localspl/printingthread.c
index b29534b519d..b351aa73512 100644
--- a/win32ss/printing/providers/localspl/printingthread.c
+++ b/win32ss/printing/providers/localspl/printingthread.c
@@ -29,7 +29,7 @@ PrintingThreadProc(PLOCAL_JOB pJob)
 
     // Prepare the pPrinterName parameter.
     // This is the string for LocalOpenPrinter to open a port (e.g. "LPT1:, Port").
-    cchPortName = wcslen(pJob->pPrinter->pPort->pwszName);
+    cchPortName = (DWORD)wcslen(pJob->pPrinter->pPort->pwszName);
     pwszPrinterPort = DllAllocSplMem(cchPortName * sizeof(WCHAR) + sizeof(wszPortAppendix));
     if (!pwszPrinterPort)
     {
diff --git a/win32ss/printing/providers/localspl/printprocessors.c b/win32ss/printing/providers/localspl/printprocessors.c
index 3540b560e06..b36b8c5c657 100644
--- a/win32ss/printing/providers/localspl/printprocessors.c
+++ b/win32ss/printing/providers/localspl/printprocessors.c
@@ -44,7 +44,7 @@ _OpenEnvironment(PCWSTR pEnvironment, PHKEY hKey)
     }
 
     // Construct the registry key of the demanded environment.
-    cchEnvironment = wcslen(pEnvironment);
+    cchEnvironment = (DWORD)wcslen(pEnvironment);
     pwszEnvironmentKey = DllAllocSplMem((cchEnvironmentsKey + cchEnvironment + 1) * sizeof(WCHAR));
     if (!pwszEnvironmentKey)
     {