diff --git a/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java b/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
index 011bc969..3b06d34a 100644
--- a/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
+++ b/core/src/main/java/org/bitcoinj/store/SPVBlockStore.java
@@ -277,7 +277,7 @@ public class SPVBlockStore implements BlockStore {
     public void close() throws BlockStoreException {
         try {
             buffer.force();
-            if (System.getProperty("os.name").toLowerCase().contains("win")) {
+            if (Utils.isWindows()) {
                 log.info("Windows mmap hack: Forcing buffer cleaning");
                 WindowsMMapHack.forceRelease(buffer);
             }
diff --git a/core/src/main/java/org/bitcoinj/utils/BlockFileLoader.java b/core/src/main/java/org/bitcoinj/utils/BlockFileLoader.java
index d23a666e..74abc459 100644
--- a/core/src/main/java/org/bitcoinj/utils/BlockFileLoader.java
+++ b/core/src/main/java/org/bitcoinj/utils/BlockFileLoader.java
@@ -55,7 +55,7 @@ public class BlockFileLoader implements Iterable<Block>, Iterator<Block> {
     public static List<File> getReferenceClientBlockFileList() {
         String defaultDataDir;
         String OS = System.getProperty("os.name").toLowerCase();
-        if (OS.indexOf("win") >= 0) {
+        if (Utils.isWindows()) {
             defaultDataDir = System.getenv("APPDATA") + "\\.bitcoin\\blocks\\";
         } else if (OS.indexOf("mac") >= 0 || (OS.indexOf("darwin") >= 0)) {
             defaultDataDir = System.getProperty("user.home") + "/Library/Application Support/Bitcoin/blocks/";