diff --git a/include/ntfs-3g/endians.h b/include/ntfs-3g/endians.h
index 4c5d7325..0be0a8f7 100644
--- a/include/ntfs-3g/endians.h
+++ b/include/ntfs-3g/endians.h
@@ -316,4 +316,6 @@
 
 #define le64_cmpz(a) (!(a))
 
+#define sle64_cmpz(a) (!(a))
+
 #endif /* defined _NTFS_ENDIANS_H */
diff --git a/libntfs-3g/attrib.c b/libntfs-3g/attrib.c
index 0e56b8be..44f3e367 100644
--- a/libntfs-3g/attrib.c
+++ b/libntfs-3g/attrib.c
@@ -742,7 +742,7 @@ int ntfs_attr_map_whole_runlist(ntfs_attr *na)
 
 		/* Are we in the first extent? */
 		if (!next_vcn) {
-			 if (a->lowest_vcn) {
+			 if (!sle64_cmpz(a->lowest_vcn)) {
 				 errno = EIO;
 				 ntfs_log_perror("First extent of inode %llu "
 					"attribute has non-zero lowest_vcn",
@@ -5427,7 +5427,7 @@ static int ntfs_attr_update_meta(ATTR_RECORD *a, ntfs_attr *na, MFT_RECORD *m,
 	ntfs_log_trace("Entering for inode 0x%llx, attr 0x%x\n", 
 		       (unsigned long long)na->ni->mft_no, na->type);
 	
-	if (a->lowest_vcn)
+	if (!sle64_cmpz(a->lowest_vcn))
 		goto out;
 
 	a->allocated_size = cpu_to_sle64(na->allocated_size);
diff --git a/libntfs-3g/mft.c b/libntfs-3g/mft.c
index 898f0a62..4263fbc6 100644
--- a/libntfs-3g/mft.c
+++ b/libntfs-3g/mft.c
@@ -760,7 +760,7 @@ static int ntfs_mft_bitmap_extend_allocation_i(ntfs_volume *vol)
 	 * We now have extended the mft bitmap allocated_size by one cluster.
 	 * Reflect this in the ntfs_attr structure and the attribute record.
 	 */
-	if (a->lowest_vcn) {
+	if (!sle64_cmpz(a->lowest_vcn)) {
 		/*
 		 * We are not in the first attribute extent, switch to it, but
 		 * first ensure the changes will make it to disk later.
@@ -1112,7 +1112,7 @@ static int ntfs_mft_data_extend_allocation(ntfs_volume *vol)
 	 * @rl is the last (non-terminator) runlist element of mft data
 	 * attribute.
 	 */
-	if (a->lowest_vcn) {
+	if (!sle64_cmpz(a->lowest_vcn)) {
 		/*
 		 * We are not in the first attribute extent, switch to it, but
 		 * first ensure the changes will make it to disk later.