diff --git a/Makefile b/Makefile
index 2d7c466..25247ab 100644
--- a/Makefile
+++ b/Makefile
@@ -32,14 +32,14 @@ BIN=$(BUILDDIR)/$(APPNAME)
 ifeq ($(TARGET),win32)
 	PLATFORM=windows
 	CC=i686-pc-mingw32-gcc
-	CFLAGS=$(COMMON_CFLAGS) -m32
+	CFLAGS=$(COMMON_CFLAGS) -m32 -DWINVER=0x500
 	LIBS=-lws2_32 -liberty
 	APPNAME=audioextract.exe
 else
 ifeq ($(TARGET),win64)
 	PLATFORM=windows
 	CC=x86_64-w64-mingw32-gcc
-	CFLAGS=$(COMMON_CFLAGS) -m64
+	CFLAGS=$(COMMON_CFLAGS) -m64 -DWINVER=0x500
 	LIBS=-lws2_32 -liberty
 	APPNAME=audioextract64.exe
 endif
diff --git a/src/audioextract_windows.c b/src/audioextract_windows.c
index 0658ffb..4d59ad4 100644
--- a/src/audioextract_windows.c
+++ b/src/audioextract_windows.c
@@ -56,8 +56,7 @@ int extract(const struct extract_options *options, size_t *numfilesptr)
 		goto error;
 	}
 
-	filesize.LowPart = GetFileSize(hFile, (LPDWORD)&(filesize.HighPart));
-	if (filesize.LowPart == INVALID_FILE_SIZE)
+	if (!GetFileSizeEx(hFile, &filesize))
 	{
 		PrintError(options->filepath);
 		goto error;
@@ -68,6 +67,13 @@ int extract(const struct extract_options *options, size_t *numfilesptr)
 		printf("%s: Skipping empty file.\n", options->filepath);
 		goto cleanup;
 	}
+	else if (filesize.QuadPart < 0)
+	{
+		fprintf(stderr, "%s: File has negative size (%"PRIi64")?\n",
+			options->filepath,
+			filesize.QuadPart);
+		goto error;
+	}
 	else if ((uint64_t)filesize.QuadPart <= options->offset)
 	{
 		printf("%s: Skipping file because offset is bigger than file.\n",
@@ -93,7 +99,7 @@ int extract(const struct extract_options *options, size_t *numfilesptr)
 		goto error;
 	}
 
-	if (do_extract(filedata, filesize.QuadPart, options, numfilesptr))
+	if (do_extract(filedata, length, options, numfilesptr))
 	{
 		goto cleanup;
 	}