diff --git a/reactos/drivers/filesystems/cdfs/cdfs.h b/reactos/drivers/filesystems/cdfs/cdfs.h
index 905a34e0c75..47d7d313041 100644
--- a/reactos/drivers/filesystems/cdfs/cdfs.h
+++ b/reactos/drivers/filesystems/cdfs/cdfs.h
@@ -143,7 +143,7 @@ typedef struct _CDINFO
   ULONG RootStart;
   ULONG RootSize;
   WCHAR VolumeLabel[MAXIMUM_VOLUME_LABEL_LENGTH / sizeof(WCHAR)];
-  ULONG VolumeLabelLength;
+  USHORT VolumeLabelLength;
   ULONG SerialNumber;
 } CDINFO, *PCDINFO;
 
diff --git a/reactos/drivers/filesystems/cdfs/create.c b/reactos/drivers/filesystems/cdfs/create.c
index 2f088622262..d7a6440d820 100644
--- a/reactos/drivers/filesystems/cdfs/create.c
+++ b/reactos/drivers/filesystems/cdfs/create.c
@@ -40,7 +40,7 @@ CdfsMakeAbsoluteFilename(PFILE_OBJECT FileObject,
                          PUNICODE_STRING RelativeFileName,
                          PUNICODE_STRING AbsoluteFileName)
 {
-    ULONG Length;
+    USHORT Length;
     PFCB Fcb;
     NTSTATUS Status;
 
diff --git a/reactos/drivers/filesystems/cdfs/dirctl.c b/reactos/drivers/filesystems/cdfs/dirctl.c
index 0160c922321..8cf71a2d0dc 100644
--- a/reactos/drivers/filesystems/cdfs/dirctl.c
+++ b/reactos/drivers/filesystems/cdfs/dirctl.c
@@ -533,7 +533,7 @@ CdfsGetBothDirectoryInformation(PFCB Fcb,
 
     /* Copy short name */
     ASSERT(Fcb->ShortNameU.Length / sizeof(WCHAR) <= 12);
-    Info->ShortNameLength = Fcb->ShortNameU.Length;
+    Info->ShortNameLength = (CCHAR)Fcb->ShortNameU.Length;
     RtlCopyMemory(Info->ShortName, Fcb->ShortNameU.Buffer, Fcb->ShortNameU.Length);
 
     return(STATUS_SUCCESS);
diff --git a/reactos/drivers/filesystems/cdfs/finfo.c b/reactos/drivers/filesystems/cdfs/finfo.c
index 25529f31607..07554c2890d 100644
--- a/reactos/drivers/filesystems/cdfs/finfo.c
+++ b/reactos/drivers/filesystems/cdfs/finfo.c
@@ -153,7 +153,7 @@ CdfsGetNameInformation(PFILE_OBJECT FileObject,
     ASSERT(Fcb != NULL);
 
     /* If buffer can't hold at least the file name length, bail out */
-    if (*BufferLength < FIELD_OFFSET(FILE_NAME_INFORMATION, FileName[0]))
+    if (*BufferLength < (ULONG)FIELD_OFFSET(FILE_NAME_INFORMATION, FileName[0]))
         return STATUS_BUFFER_OVERFLOW;
 
     /* Calculate file name length in bytes */
diff --git a/reactos/drivers/filesystems/cdfs/fsctl.c b/reactos/drivers/filesystems/cdfs/fsctl.c
index 856379187af..c15e84f6381 100644
--- a/reactos/drivers/filesystems/cdfs/fsctl.c
+++ b/reactos/drivers/filesystems/cdfs/fsctl.c
@@ -46,7 +46,7 @@ CdfsGetPVDData(PUCHAR Buffer,
                PCDINFO CdInfo)
 {
     PPVD Pvd;
-    ULONG i;
+    USHORT i;
     PUCHAR pc;
     PWCHAR pw;
 
diff --git a/reactos/drivers/filesystems/fastfat/finfo.c b/reactos/drivers/filesystems/fastfat/finfo.c
index cdadc87e4fa..61be39acbad 100644
--- a/reactos/drivers/filesystems/fastfat/finfo.c
+++ b/reactos/drivers/filesystems/fastfat/finfo.c
@@ -379,7 +379,7 @@ VfatGetNameInformation(PFILE_OBJECT FileObject,
   ASSERT(FCB != NULL);
 
   /* If buffer can't hold at least the file name length, bail out */
-  if (*BufferLength < FIELD_OFFSET(FILE_NAME_INFORMATION, FileName[0]))
+  if (*BufferLength < (ULONG)FIELD_OFFSET(FILE_NAME_INFORMATION, FileName[0]))
     return STATUS_BUFFER_OVERFLOW;
 
   /* Save file name length, and as much file len, as buffer length allows */
diff --git a/reactos/drivers/filesystems/npfs/dirctl.c b/reactos/drivers/filesystems/npfs/dirctl.c
index ef7b1317774..2b0eec08ed9 100644
--- a/reactos/drivers/filesystems/npfs/dirctl.c
+++ b/reactos/drivers/filesystems/npfs/dirctl.c
@@ -21,7 +21,7 @@ NpfsQueryDirectory(PNPFS_CCB Ccb,
                    PULONG Size)
 {
     PIO_STACK_LOCATION Stack;
-    LONG BufferLength = 0;
+    ULONG BufferLength = 0;
     PUNICODE_STRING SearchPattern = NULL;
     FILE_INFORMATION_CLASS FileInformationClass;
     ULONG FileIndex = 0;
diff --git a/reactos/drivers/filesystems/npfs/rw.c b/reactos/drivers/filesystems/npfs/rw.c
index ea3449adb70..48c1bbc1897 100644
--- a/reactos/drivers/filesystems/npfs/rw.c
+++ b/reactos/drivers/filesystems/npfs/rw.c
@@ -21,7 +21,7 @@ VOID HexDump(PUCHAR Buffer, ULONG Length)
     CHAR Line[65];
     UCHAR ch;
     const char Hex[] = "0123456789ABCDEF";
-    int i, j;
+    ULONG i, j;
 
     DbgPrint("---------------\n");