diff --git a/dll/win32/browseui/parsecmdline.cpp b/dll/win32/browseui/parsecmdline.cpp
index acf617607fe..ad2b4fa4756 100644
--- a/dll/win32/browseui/parsecmdline.cpp
+++ b/dll/win32/browseui/parsecmdline.cpp
@@ -226,7 +226,7 @@ static LPITEMIDLIST _GetDocumentsPidl()
 * SHExplorerParseCmdLine		[BROWSEUI.107]
 */
 extern "C"
-UINT
+UINT_PTR
 WINAPI
 SHExplorerParseCmdLine(ExplorerCommandLineParseResults * pInfo)
 {
diff --git a/sdk/include/ndk/rtltypes.h b/sdk/include/ndk/rtltypes.h
index b526f9ea04f..7070564389b 100644
--- a/sdk/include/ndk/rtltypes.h
+++ b/sdk/include/ndk/rtltypes.h
@@ -310,7 +310,7 @@ C_ASSERT(HEAP_CREATE_VALID_MASK == 0x0007F0FF);
 //
 // Activation Contexts
 //
-#define INVALID_ACTIVATION_CONTEXT                          (PVOID)0xFFFFFFFF
+#define INVALID_ACTIVATION_CONTEXT                          ((PVOID)(LONG_PTR)-1)
 
 //
 // C++ CONST casting
diff --git a/sdk/include/reactos/browseui_undoc.h b/sdk/include/reactos/browseui_undoc.h
index 4ea2dcf6057..0bc1d12db6d 100644
--- a/sdk/include/reactos/browseui_undoc.h
+++ b/sdk/include/reactos/browseui_undoc.h
@@ -107,7 +107,7 @@ void WINAPI InitOCHostClass(long param8);
 long WINAPI SHOpenFolderWindow(PIE_THREAD_PARAM_BLOCK parameters);
 void WINAPI SHCreateSavedWindows(void);
 BOOL WINAPI SHCreateFromDesktop(PEXPLORER_CMDLINE_PARSE_RESULTS parseResults);
-UINT WINAPI SHExplorerParseCmdLine(PEXPLORER_CMDLINE_PARSE_RESULTS pParseResults);
+UINT_PTR WINAPI SHExplorerParseCmdLine(PEXPLORER_CMDLINE_PARSE_RESULTS pParseResults);
 void WINAPI UEMRegisterNotify(long param8, long paramC);
 HRESULT WINAPI SHCreateBandForPidl(LPCITEMIDLIST param8, IUnknown *paramC, BOOL param10);
 HRESULT WINAPI SHPidlFromDataObject(IDataObject *param8, long *paramC, long param10, FILEDESCRIPTORW *param14);
diff --git a/sdk/lib/inflib/infget.c b/sdk/lib/inflib/infget.c
index f148c59273a..5e1ccdbf3b2 100644
--- a/sdk/lib/inflib/infget.c
+++ b/sdk/lib/inflib/infget.c
@@ -13,11 +13,11 @@
 #define NDEBUG
 #include <debug.h>
 
-static unsigned int
+static size_t
 InfpSubstituteString(PINFCACHE Inf,
                      const WCHAR *text,
                      WCHAR *buffer,
-                     unsigned int size);
+                     size_t size);
 
 static void
 ShortToHex(PWCHAR Buffer,
@@ -36,7 +36,7 @@ ShortToHex(PWCHAR Buffer,
 static PCWSTR
 InfpGetSubstitutionString(PINFCACHE Inf,
                           PCWSTR str,
-                          unsigned int *len,
+                          size_t *len,
                           BOOL no_trailing_slash)
 {
     static const WCHAR percent = '%';
@@ -105,7 +105,7 @@ InfpGetSubstitutionString(PINFCACHE Inf,
     if (Status == STATUS_SUCCESS)
     {
         *len = strlenW(Data);
-        DPRINT("Substitute: %S  Length: %ul\n", Data, *len);
+        DPRINT("Substitute: %S  Length: %zu\n", Data, *len);
         return Data;
     }
 
@@ -116,14 +116,14 @@ InfpGetSubstitutionString(PINFCACHE Inf,
 /* do string substitutions on the specified text */
 /* the buffer is assumed to be large enough */
 /* returns necessary length not including terminating null */
-static unsigned int
+static size_t
 InfpSubstituteString(PINFCACHE Inf,
                      PCWSTR text,
                      PWSTR buffer,
-                     unsigned int size)
+                     size_t size)
 {
     const WCHAR *start, *subst, *p;
-    unsigned int len, total = 0;
+    size_t len, total = 0;
     int inside = 0;
 
     if (!buffer) size = MAX_INF_STRING_LENGTH + 1;
@@ -133,7 +133,7 @@ InfpSubstituteString(PINFCACHE Inf,
         inside = !inside;
         if (inside)  /* start of a %xx% string */
         {
-            len = (unsigned int)(p - start);
+            len = (p - start);
             if (len > size - 1) len = size - 1;
             if (buffer) memcpy( buffer + total, start, len * sizeof(WCHAR) );
             total += len;
@@ -142,12 +142,12 @@ InfpSubstituteString(PINFCACHE Inf,
         }
         else /* end of the %xx% string, find substitution */
         {
-            len = (unsigned int)(p - start - 1);
+            len = (p - start - 1);
             subst = InfpGetSubstitutionString( Inf, start + 1, &len, p[1] == '\\' );
             if (!subst)
             {
                 subst = start;
-                len = (unsigned int)(p - start + 1);
+                len = (p - start + 1);
             }
             if (len > size - 1) len = size - 1;
             if (buffer) memcpy( buffer + total, subst, len * sizeof(WCHAR) );
@@ -546,7 +546,7 @@ InfpGetStringField(PINFCONTEXT Context,
   PINFCACHEFIELD CacheField;
   ULONG Index;
   PWCHAR Ptr;
-  ULONG Size;
+  SIZE_T Size;
 
   if (Context == NULL || Context->Line == NULL)
     {
diff --git a/sdk/lib/skiplist/skiplist_test.c b/sdk/lib/skiplist/skiplist_test.c
index 17d9337463e..5413910ea77 100644
--- a/sdk/lib/skiplist/skiplist_test.c
+++ b/sdk/lib/skiplist/skiplist_test.c
@@ -31,7 +31,7 @@ DumpSkiplist(PSKIPLIST Skiplist)
             for (j = 1; j < pNode->Distance[i]; j++)
                 printf("---");
 
-            printf("%02lu", (DWORD)pNode->Next[i]->Element);
+            printf("%02Iu", (DWORD_PTR)pNode->Next[i]->Element);
 
             pNode = pNode->Next[i];
         }
@@ -51,7 +51,7 @@ MyAlloc(DWORD Size)
 int WINAPI
 MyCompare(PVOID A, PVOID B)
 {
-    return (DWORD)A - (DWORD)B;
+    return (DWORD_PTR)A - (DWORD_PTR)B;
 }
 
 void WINAPI
@@ -63,7 +63,7 @@ MyFree(PVOID Ptr)
 int
 main()
 {
-    DWORD Element;
+    PVOID Element;
     DWORD ElementIndex;
     DWORD i;
     SKIPLIST Skiplist;
@@ -74,23 +74,23 @@ main()
 
     // Insert some random elements with random numbers.
     for (i = 0; i < 40; i++)
-        InsertElementSkiplist(&Skiplist, (PVOID)(rand() % 100));
+        InsertElementSkiplist(&Skiplist, UlongToPtr(rand() % 100));
 
     // Delete all with index 0 to 29.
     for (i = 0; i < 30; i++)
-        DeleteElementSkiplist(&Skiplist, (PVOID)i);
+        DeleteElementSkiplist(&Skiplist, UlongToPtr(i));
 
     // Insert some more random elements.
     for (i = 0; i < 40; i++)
-        InsertElementSkiplist(&Skiplist, (PVOID)(rand() % 100));
+        InsertElementSkiplist(&Skiplist, UlongToPtr(rand() % 100));
 
     // Output the third element (with zero-based index 2).
     pNode = LookupNodeByIndexSkiplist(&Skiplist, 2);
-    printf("Element = %lu for index 2\n", (DWORD)pNode->Element);
+    printf("Element = %Iu for index 2\n", (DWORD_PTR)pNode->Element);
 
     // Check if an element with number 44 is in the list and output its index.
-    Element = (DWORD)LookupElementSkiplist(&Skiplist, (PVOID)44, &ElementIndex);
-    printf("Element = %lu, ElementIndex = %lu\n\n", Element, ElementIndex);
+    Element = LookupElementSkiplist(&Skiplist, UlongToPtr(44), &ElementIndex);
+    printf("Element = %p, ElementIndex = %lu\n\n", Element, ElementIndex);
 
     DumpSkiplist(&Skiplist);